Slippery Slope and Perpetual Comeback
Sirlin
If a game has slippery slope, it means that falling behind causes you to fall even further behind.
For example, imagine that every time your team scored in basketball that the opponent’s team lost a player. In that game, falling behind is doubly bad because each basket counts for score AND it makes the opposing team less able to score points of its own. The actual game of basketball does not have this screwy feature though, so real basketball does not have slippery slope. Scoring in real basketball puts you closer to winning but does not at all hamper your opponents’ ability to score.
Slippery slope is another name for positive feedback, a loop that amplifies itself as in a nuclear reaction. Because people confuse the terms positive and negative feedback so easily, I prefer the more descriptive term slippery slope.
Slippery slope is usually a bad property in a game. If a game has a powerful slippery slope effect, that means that when one player gets a small early lead, he is more likely to get an even bigger lead, which in turn makes him more likely still to get yet an even bigger lead, and so on. In a game like this, the real victor of the game is decided early on, and the rest of the game is futile to play out (or to watch).
StarCraft and Chess do have slippery slope. They manage to be good games anyway, despite this anti-climactic property. In Chess, when a player loses a piece, his ability to attack, defend, and control space on the board is slightly reduced. Sure, there are many other factors in Chess--positioning, momentum, pawn structure--that determine if a player is actually “losing,” but losing a piece does have an effect. Clearly, losing a lot of pieces, say 8, puts a player at a significant disadvantage. It’s pretty hard to make a comeback in Chess, and a game is usually “won” many, many moves before the actual checkmate move.
This is why there are a lot of forfeits in Chess. Good players don’t actually play out the pointless part of the endgame when they recognize the opponent will definitely win. Chess players would say that forfeits being a regular part of the game is fine and not awkward, but it’s a disappointing quality compared to games without slippery slope. Still, Chess is a pretty good game anyway.
This guy just lost a Chess piece.
StarCraft also has slippery slope. When you lose a unit, you are penalized doubly. First, you are closer to losing (having no units at all is so crippling as to be virtually the same as the actual loss condition of losing all your buildings). Second, you are less able to attack and defend because the unit you lost was not just part of a score, but also part of the actual gameplay of attacking and defending.
In basketball, the score is completely separate from the gameplay. Your ability to score points doesn’t depend at all on what the current score is. You could be ahead by 20 points or behind by 20 points and have the same chances of scoring more points. But in StarCraft (and Chess), the score is bound up with the gameplay. Losing units pushes you closer to loss AND makes it harder to fight back.
StarCraft has even more severe slippery slope when it comes to the game’s economy. Imagine that your opponent rushes you (sends an early attack to your base) and you fend it off. Let’s say you each lost about the same value of units in the exchange, except that you also lost one worker unit. In a different type of game, this might equate to being one “point” behind. But in StarCraft, that can be a crippling loss because gathering minerals is nearly exponential. Your opponent is ahead of you in the resource curve, increasing his earnings faster than you are. You’ve fallen down a very slippery slope here, where an early disadvantage becomes more magnified as the game goes on.
Fighting Games
Fighting games don’t usually have slippery slope. In Street Fighter, for example, your character still has all of his moves even when he’s about to lose. Getting hit puts you behind in life totals (in “score”) but doesn’t limit your gameplay options in the way that losing a piece in Chess does or losing a unit in StarCraft does. An unusual example of a fighting game that does have slippery slope is Bushido Blade. In that game, getting hit can cause you limp around or lose the use of an arm. This is extremely rare in the fighting game genre though, and for good reason.
While it might be "realistic" for a nearly dead character to limp, move slowly, and have generally less effective moves, it's not fun. (At least in Bushido Blade's case, this part of the game lasts only a couple seconds, then you lose.) Meanwhile in Street Fighter, comebacks are frequent and games are often "anybody's game" until the last moment. Street Fighter does have some very minimal slippery slope aspects (if you're very near death you have to worry about taking damage from blocked moves which aren't a threat if you have full life), but overall it's pretty "slippery slope neutral."
There is one fighting game that stands out as an exception: Marvel vs. Capcom 2. In this game, each player chooses 3 characters. At any given time, one character is active and on-screen, and the other two are off-screen, healing back some lost energy. The off-screen characters can be called in to do an assist move, then the jump off screen again. The main character can attack in parallel with the assist character, allowing for a wide variety of tricks and traps. The player can switch the active character at any time, and he loses the game when he loses all three characters. But here, slippery slope rears its bitter head. When one player is down to his last character and the other player has two or even all three of his characters, the first player is at a huge disadvantage. The first player has can no longer attack in parallel with his assists, which often means he has no hope of winning. Comebacks in MvC2 are quite rare and games often "end" before they are technically over.
Fighting games with "ring out" such as Virtua Fighter and Soul Calibur as especially devoid of slippery slope properties. In these games, a player instantly loses if his character is ever pushed out of the ring, no matter how much energy he has. Basically, no matter how far behind you are, no matter how close you are to losing, you always have a 100% damage move: ring out. Long ago, I thought this concept was "cheap" and served only to shorten games while adding little benefit, but actually the threat of ring out adds quite a bit to both these games. Since the threat of ring out is so great, another whole element of positioning is added to the game. A player must fight both to do damage to his opponent, and fight for position to avoid ring out.
Limited Slippery Slope
Fighting games do have very localized, limited kind of slippery slope that’s actually a good quality. If a game truly has no slippery slope whatsoever at any point, then it can feel like a series of disconnected decisions. It’s interesting though, if a decision you make at one point in a game echoes forward through time, and can influence later moves in the game. The problem is if this influence is allowed to snowball into a greater and greater advantage.
In limited slippery slope, there is a cap on how far you can slip and the effect is temporary. In Street Fighter, getting knocked down (hit by a sweep) does have a bit of slippery slope. You lose health (“score”) but you also have temporary limitations on what your character can do. Your character falls down, then gets up into what is usually a disadvantageous situation. The two things that are important about this are: 1) after the knockdown is over, you regain all your moves and 2) you cannot get doubly knocked down.
Ken is at a temporary disadvantage here from being knocked down, but the disadvantage can't snowball into deeper levels of knockdown (there aren't any) and it fades with time.
Hitting the opponent with a sweep does echo forward through time, but this advantage is reset soon after and can’t snowball into “getting REALLY knocked down” because there is no such thing as degrees of knockdown. If you are already knocked down, you can't be knocked down "even more."
Another example is backing the opponent into the corner (the edge of the stage). If you do this, you have a natural advantage because the opponent has fewer movement options. But again, there’s a limit here. Once the opponent is in the corner, he can’t be “more in the corner.” There’s a limit to how disadvantaged he can get.
An even more basic example is anytime you block a move that has a fair amount of recovery. In these case, you recover from your blockstun before the opponent recovers from his move, so you have a few frames to act first. This gives you an advantage because if you both try to do a move of the same speed, yours will win (it will start first). Your good decision to block echoed forward into the future, but the effect is very fleeting. Even one second later, this advantage fades.
So fighting games are full of small, temporary slippery slope effects that actually help the game. And yet, on the macro level, they do not have the real kind of slippery slope, the permanent kind that snowballs until the game ends. Compare this to Chess where you don’t just get your captured pieces back a few turns later.
And RTS Without Slippery Slope
Here’s an idea for turning the full-on slippery slope (usually bad) into the limited kind (usually good). Both players start with the same amount of resources to buy units. When your units are destroyed, your resources are refunded. A delay in the timing of this refund combined with the build-time for making new units means that losing units really is a disadvantage, but that the disadvantage fades over time, similar in nature to getting knocked down in a fighting game. The real-time strategy game World in Conflict does exactly this, but I’ve never actually played it.
My point here isn't about whether World in Conflict is a good game, or even whether the exact refund system stated above is good. It just shows that it is possible to remove slippery slope from an RTS if you try hard enough. Someone very dedicated to that problem could probably come up with an even better way to remove it that results in a deeper game, rather than a shallower one.
Perpetual Comeback
The opposite of slippery slope, I call perpetual comeback. That’s just a more descriptive term for negative feedback. (Also, negative feedback sounds like a bad thing, but it’s usually a good quality in games, so it’s helpful to have a term that doesn’t sound negative.) A thermostat uses negative feedback to keep the temperature of a room from spiraling out of control.
Perpetual comeback, then, is a quality in which being behind actually gives you an advantage. I’d like to draw a distinction between two types of this effect, though. In one, when you are behind, a force pushes on you to help improve your position. An example of this is the Fatboy mutator in Unreal Tournament. In that first-person shooter mod, when you kill an enemy, you become fatter and easier to hit. When you die, you become skinnier and harder to hit. Multiple hits magnify the effect, so if you die over and over you get skinner and skinner. Note that even if you die a lot, you are still losing (your score is not helped), but you do have an advantage (harder to hit).
Beautiful, but dangerous.
A similar example is any version of Mario Kart. The further behind you are, the more powerful the items you get. In last place, you can get the powerful blue turtle shell which has homing powers to zero in on the first place racer. Meanwhile, the first place racer gets only weak items.
Advance Wars: Dual Strike on the Nintendo DS has a similar feature. Each side has a powerful “tag attack” that’s tied to a meter. When you get attacked, your meter fills up at twice the rate as usual, so the losing player will have faster access to this powerful attack, giving him a chance to make a comeback.
In all three of these examples, the games have a force that help out players who are behind and hinder players who are ahead. This is generally a good type of force to have, because it makes games closer, and small early mistakes are not crippling. That said, maybe the effect is too extreme in Mario Kart, or maybe it creates strange artifacts such as avoiding 1st place on purpose for most of the race. And the power of the tag attacks in Advance Wars might be too extreme, making them dominate the game. Tuning issues aside, the concept is still sound and when it’s done right, it can make matches closer and more exciting.
Perpetual Comeback Extreme
There is a different type of perpetual comeback that is far more extreme and far more rare. That’s when getting closer to losing doesn’t JUST give you helping hand, but instead actually puts you ahead. I think the best example of this strange property is Puzzle Fighter.
Puzzle Fighter is, in my opinion, the best puzzle game ever made and I felt that way long before I was lead designer of Puzzle Fighter HD Remix. The game seems standard enough--it's one of those games where each player has a basin that pieces fall into. There are four different colors of pieces, and you try to build big, single colored rectangles (power gems). You can then shatter those rectangles with special pieces called crash gems. The more you break, the more junk you drop on the opponent's side. When your side fills to the top, you lose.
Several factors come together to create perpetual comeback (the extreme version!) in Puzzle Fighter. Firstly, each "character" (there 11 to choose from, including secret characters) has a different "drop pattern." A drop pattern is the pattern of colored blocks that a character will send to his enemy when that character shatters blocks on his own side. For example, Ken's drop pattern is horizontal row of red, followed by a horizontal row of green, then yellow, then blue. Every time Ken sends 6 or fewer blocks to his opponent, he'll send a horizontal row of red. Every time Ken sends 12 blocks, he'll send a row of red, then a row of yellow. Since the enemy knows this, he can plan for it. He can build his blocks such that Ken's attack will actually help rather than hurt. There's one catch: when you send blocks to the opponent, they appear in the form of "counter gems," which can't be broken immediately by normal means, and can't be incorporated into deadly power gems. After about 5 moves, the counter gems change into regular gems.
The other very critical property is that power gems broken higher up on the screen do more much more damage (send many more counter gems) than gems broken at the bottom of the screen. So consider what attacking is actually like in this game. Attacks are really only temporarily damaging, until the counter gems turn into regular gems. At that point, the opponent will probably be able to incorporate the gems into their own plans, since the opponent knows your drop pattern. Even if the opponent isn't able to benefit from your attack in that way, he can still "dig himself out" of trouble by breaking all the stuff you sent him. By filling up his screen most of the way you've basically given him more potential ammunition to fire at you. What's more, as he is nearest to death, his attacks will be the most damaging due to the height bonus. Gems broken at the very top of the screen do significant damage.
Puzzle Fighter has the extremely unusual property that "almost losing" looks exactly like "almost winning." Let's say you break a whole slew of power gems and send a large attack at your opponent. You're screen is now almost empty. You're winning right? His screen is nearly to the top--almost full. He's losing, right? Well, he is on the verge of losing, but he has all the ammunition and he has the height bonus, whereas you have almost nothing left to defend with. In effect, your opponent is both "losing" and "winning" at the same time. Very curious, indeed!
Ken (left) was close to losing, but he got the yellow crash gem he needed just in time. Donovan (right) will lose.
It turns out the best way to play Puzzle Fighter is to very carefully never attack until you can make it count. All those little jabs you make just help the opponent in the long run. You've got to save up for a huge, 1-2 punch. You need to send a big attack that almost kills them, then immediately send another attack that finishes them off. 1, 2! The point is that Puzzle Fighter is a high energy, edge-of-your seat game. Your opponent very often has enough attack to kill you, so you have to have enough defense to stop them. Whenever the scales start to tip in your opponent's favor, they have also, weirdly, tipped in your favor as well, in some sense. A game of Puzzle Fighter is never over until the last moment. Comebacks are the name of the game, and the excitement goes to the very last second almost every time.
Conclusion
Slippery slope is a force that punishes players who fall behind, making them even more likely to fall further behind. Left unchecked, this makes for matches where the real victor is decided long before the game actually ends, leading to either boring endgame play, or lots of forfeits. While fighting games lack this overall slippery slope, they do have several forms of temporary, limited slippery slope that improves gameplay. This limited slippery slope probably exists in other genres as well, but could be a conscious design choice for future games. Finally, perpetual comeback, the opposite of slippery slope, is a force that helps losing players and puts the brakes on winning players, making for close matches. This property can easily go wrong if tuned improperly, but if done well, it leads to closer, more exciting matches. Puzzle Fighter takes this concept to an extreme, by making winning look almost the same as losing.
Reader Comments (113)
Insight struck.
I think, you have to at least differentiate between score-based and objective-based games. Examples of the former are fighting games, puzzles, card games, quake-style mp shooters; of the latter - chess, wargames, most RTS, tactical shooters.
A bit of necromancy:
"Can you build 4 more later? Yes. But he can build 4 more too."
No. He can build 3 more. His units are more expensive than mine in this scenario, thanks to the "hidden" cost that the supply mechanic brings.
Think about it like this: how much does a Zealot cost? Your instant answer is probably "200 minerals". Well... really, it's 200 minerals and 2 supply. How can we quantify supply? Well, the cheapest source of supply, a pylon, costs 100 minerals for 8 supply. That means that a Zealot to make our army larger costs 225 minerals... but a replacement Zealot costs 200 minerals.
Factor in the time it takes him to walk across the map to my base (which gives me an extra production cycle), and it's more like I can build 5 units to his 3. Obviously, in this situation, my chances are pretty dire- but it never should have gotten to the "he has over double the army I do" situation in the first place; he should have just killed me about 5 minutes earlier if it got to that insane of a situation. Give it a saner initial condition- something like 8 units vs. 7 units- and you'll see it stabilize out quite nicely.
Sirlin I do not dispute there is a slippery slope as you define. However the slippery slope in neither chess nor starcraft makes a "bad" design. Even taking Starcraft 2, the sequel with less mechanic requirement and less pronounced defender's advantage, the slippery slope aspect did not prevent the game from being exciting. From this article and this article alone I get the sense that in your mind starcraft games are decided in a giant combat and whoever wins that wins the game necessarily, or someone can _never_ come back from a successful early worker harassment. That is simply untrue.
Then again, this is the interpretation I made, but if you do mean something else, the expression here is far from adequate.
Hi, this post was very inspirating to me. I'm starting to speak about strategy in a new blog and my first though was about this precise topic. And this question : "When is a player nealry automatically winning?".
One answer is given by your sliperry slope theory: putting the opponent in such a situation he can't reach you. And, it looks like obvious: if you put yourself in a situation your opponent can't reach you.
So, just to add something on your excellent topic, i say there is another game design problem regarding winning or losing: just the reverse of sliperry slope : The virtuous circle, or at least the "advantages over advantages". When some advantage give another advantage which could lead to another, and so on. Even if the opponent hasn't been hurt yet, you could already be winning the game.
One outrageous virtuous circle appears when games don't handle well the money system: someone rich keeps becoming richer, even if other players are playing well. It can happen in games where you can't directly reach your opponent (my personal example is about counter-strike manager where rich people just keep being richer, regarding others).
To conclude for every player out there: one of your main goal when you are discovering a game is to look for sliperry slope and virtuous circle. Then, with this knowledge, you can build solid strategies...
For those who speak french: here's a topic about virtuous circle.
Thanks for your topics Sirlin and keep up the good job.
JdlF, yes and you can read about that design problem in the very article you just commented on here, lol. I called the virtuous circle concept "perpetual comeback" here.
The real terms are negative feedback and positive feedback, but everyone mixes up which one of those is which, so I preferred more colorful terms instead.
Thanks for the links though!
Yeah, but you define the perpetual comeback as "Perpetual comeback, then, is a quality in which being behind actually gives you an advantage."
While i question myself on what we could call outrageous advantages, when someone will lose/drop, not because of doing bad but instead because of the opponent finding a tip or a perfect combo.
Example: An online game where you just can't challenge an older player, not because of his skills but his amount of hours (linked to gold/equipment/unlocked capacities). Another example would be finding an infinite combo in the game (it happens in card games like magic).
In both case, the loser wasn't in a slippery slope situation. Instead it was his opponent who was in a kind of ropeway/aerial tramway. This is what i call the exact opposite of your slippery slope theory :), but that's my personal opinion ^^.
And, in my point of view, i see perpetual comeback has a limitation to a sliperry slope situation: it helps the losing player to come back. Not as the opposite, i think it's more like a sliperry slope's characteristic: having or not perpetual comeback. While a virtuous circle would be the opposite of a slippery slope situation.
I agree most of the time you have both: one sliperry slope for the loser and one virtuous circle for the winner (as a result of each other). But not in all situations and that was just my "add" to generalize a bit more your theory :).
Winning circle are especially powerful when you're playing with a large number of opponent. When you can't dominate every player and put them in a slippery slope situation. Therefore you can look for the opposite: a virtuous circle giving you global advantages... Like economies of scale for example.
@Sirlin: Actually, you made a small mistake with your last comment: the virtuous circle and vicious circle are both positive feedback loops i.e. slippery slopes. I will use the analogy of "wealth".
The rich get richer - virtuous cycle.
The poor get poorer - vicious cycle.
In a -competitive- environment, either or both of these things will lead to what you term a "slippery slope", because in a competitive environment it's effectively your wealth minus your opponent's wealth - this difference is your 'advantage' (or disadvantage, if it's negative).
If you are both poor, but one is poorer than the other, then the gap between your wealth increases since the vicious cycle applies to both of you.
If you are both rich, but one is richer than the other, then the gap between your wealth also increases since the virtuous cycle applies to both of you.
If one of you is poor and the other is rich, then the gap between your wealth also increases, but far more significantly than in the first two cases.
All of these are slippery slopes, because the difference in wealth (the advantage or disadvantage) increases over time. However, I would class these as independent slippery slopes, since they are independent of competitive interaction (one does not get richer at the expense of the other).
A game example of these two circles at work might be some sort of PvE game with monetary rewards and monetary penalties where you are still essentially competing with one another (on some sort of high-score board, perhaps) but without interacting with one another.
Virtuous circle: better equipment = more kills = more money = better equipment = more kills and so on
Vicious circle: worse equipment = more deaths = less money = worse equipment = less kills and so on
Of course, there are limits (defined by game difficulty and player skill or strategy or whatever is involved) on these circles, otherwise a starting player would never get out of the vicious circle into the virtuous circle.
But there are certainly slippery slopes that are dependent upon competitive interaction (for a lesser example, take the above example, but instead pit two teams against one another instead of PvE), and these directly competitive types of slippery slope are what I think you've focused on in your article and responses.
I agree that perpetual comebacks make for more exciting games in general. However, the presence of slippery slopes -may- place a greater emphasis on strategy (long-term gain) than tactics (short-term gain). Consistent short-term gains will inevitably lead to victory. If you were to design a strategy game, then it's really just a balancing act of how much of each of these two things you want (and perhaps whether players get the choice of either in various situations), and how much and how well you can mesh these two things together; and finally, whether the presence of slippery slopes (and their resulting phenomenon: lame-duck situations) are acceptable for the type of game you're designing.
After reading this article and many of the comments, I'm interested in whether there are games that employ perpetual comebacks (negative feedback) and slippery slopes (positive feedback) simultaneously (*or in response to player decisions) to approximate a neutral (*or potentially neutral) slope; and whether or not that could be considered good design.
Relic's recent RTS series-- Company of Heroes and Dawn of War 2-- have a peculiar way of reducing the slippery slope AND increasing the comeback potential.
Every soldier you have in a squad except for your commander costs upkeep. So if you're winning with that large army, even controlling more capture points you can actually be earning LESS than the opponent because of upkeep.
Similarly, because the scoring control points are separate from the resource control points, in order to win you have to focus on capturing and defending these points, giving the other player the opportunity to grab resource points of varying kinds.
This combines with the first point too, meaning that games between skilled players are never over until the last victory point ticks down. There's plenty of unique ways to provide more competitive gameplay.
There is a popular FPS series known as Call Of Duty nowadays. and it has a LOT of slippery slope, even beyond the norm for such a game.
Most FPS games have dying put you at a double disadvantage. you lose your stuff, and your opponent gets a point. But CoD has killstreaks. rewards for making multiple kills without dieing. these help you out, putting a winning player even closer to winning. And the more kills in a row you get, the more powerful the rewards are. One version even lets you call in a nuke for an instant win for your team regardless of time left, if you get a big enough kill streak.. the ultimate in slippery slope.
Feels strange to chime in now, but this has gone on for 3 years until the last post, so why not? :)
Objectively, from a game-mechanics perspective,
I think another simpler way (along with the several others outlined in previous posts) to look at slippery slopes and comebacks is to realize that in a slippery slope game you cannot make up for your disadvantage unless your opponent makes a mistake and you don't.
What objectively offsets, in a way, the Sl. Sl. Factor in Starcraft is that it's a very competitive real-time strategy where players are bound to make mistakes and the negative values of those mistakes are impossible to calculate in the heat of a deathmatch.
But, in theory (heh), if two players are of the exact same skill level, if one makes a mistake for some reason, and the other one doesn't (or if, after the mistake, the two players trade equally small mistakes blow for blow), then the first player will lose. Will. Lose.
Not so for games where the slippery slope is pushed in the 1-to-5-percent of total competitions. The famous Daigo comeback happened not because Chun-Li made mistakes (she actually did something that gave her the biggest chance for victory), but because Daigo neutralized his mistakes from earlier on. Each instance of wrong timing at the start he made up for at the end.
Subjectively, from a player perspective,
The time-drag "equivalence" between Sl. Sl. games and SF, for example, is simply not an equivalence. The 3-second 100%-deadly combo is 1/33 of a round, equivalent to about 1.5-2 minutes of SC gameplay, if that much.
More importantly, slippery slopes have a high ratio of teeth-grinding-to-fun, both from players and from spectators.
In SC, newbies and even intermediates cannot watch expert games without explanatory commentary. Experts don't have the patience to watch or suffer through games against newbies-intermediates.
Not all people have the grace to forfeit a game, sour losers abound, people tend to overestimate their mistakes and underestimate their opponent's exactly because of the slippery slope mechanic. "Shit, he killed 6 of my probes, shit, shit, shit, shit, fuck that guy!!! Fuck him!!!" While at the same time the other guy forgot that 3 of his own probes are just idling around his base. But you're ready to forfeit the game just because he messed up your tidy build-order.
From then on it's either forfeit or hoping he'll mess up somehow and you won't, which is just all kinds of wrong yomi. Instead of "All right, so he has these X options available and I can counter him with these X of mine." you're thinking "Oh God, please let him screw up somehow, please!!!" And that sort of stressful thinking messes up your own game further.
This, in turn, brings about my own basketful of sour grapes, and that's the out-of-game resources, APM and attention. That stuff has to be drilled, physically. It's stressful and not fun to me.
I was better at Age of Empires II, to be honest, and did the drills for a time. Turned out that it did me no good against competitive players, because they had done insane amounts of grind before I even learned of the game and the prospect of catching up was extremely daunting. "So he's practiced for 4 hours a day for how many months now?!?" (And that's AoE, a much more APM-friendly game than SC, with some significant interface advantages over SC.)
The same goes for SF, actually, but there at least your lack of coordination doesn't doom you if it's a slip or two (or three even), also not making any more mistakes often is enough to even win, and if you are truly hopeless, the fight is over in 10 seconds or so. But to exit a match annoyed and frustrated because with a single petty, probe-killing skirmish the opponent kicked your enthusiasm in the nuts...
The RTSs like SC are played the same way as sports, literally, only without their benefits. (Outside Korea, at least.) The lower-than-expert level of gameplay is simply not very engaging (anymore), not to mention the steep learning curve (grind) to actually reach a decent level of mastery. However rich and multifarious the game is in itself, to be able to explore that richness, you need that one kill-all dominant non-counterable strategy, the high APM and a very specific sort of attention-span that simply takes too long to learn, unless the game is your number one hobby priority (or even your number one priority, period).
Any game with a timer and no ring out condition has extreme amounts of slippery slope. All you have to do is score one point and then turtle. There is no reason to try and attack anymore so you can dedicate 100% of your resources to defence. The enemy is now guaranteed to lose because even if he allocates all of his resources to offence he will still fail due to the defender advantage and because unlike the other side he does have a deadline.
......
Mobas are ABOUT the slippery slope, but have a form of high templar gameplay as well. You spend 40 minutes trying to build up a gold advantage, even sometimes picking heroes that are a liability later on just so you can gank the enemy a few times early on and get ahead, and this gold advantage makes the game-deciding battle much easier. But still if the carry makes a mistake and gets caught and destroyed at the start of the battle it's gg.
This would be like fighting a few games of SF to decide how much health each player should have at the start of the match that actually counts. Even if you're way behind you can still win.
On paper, at least. In practice if you managed to fall behind in the first place you're not suddenly going to play immensely better: while you CAN still win even if you have a 30 kill disadvantage you're probably not GOING to win because you suck. Which is why these games have a concede option. Dota2 does not have a concede option because it wants to encourage fighting back, but when you are behind there is about a 10% chance to win and a 90% chance to get stomped over and over while the other team laughs at you and your own team insults you.
Therefore the argument of whether or not a game makes it harder to come back than to gain an advantage in the first place is mostly irrelevant. If a game is 100% skill based then whoever makes the first mistake will keep making mistakes until he loses REGARDLESS of the amount of slippery slope. The only situation where this does not happen is if the game allows making sacrifices in return for benefits later or elsewhere so you are in effect making it harder on yourself right away in order to secure an easy win down the road. That's slippery slope - if you can survive while at a disadvantage you will most certainly survive when your strategic advantage kicks in, so as soon as your strategy starts working it's gg.
But without this slippery slope the game would be boring because one side would just simply fall behind and keep falling behind until he loses.
Gonna throw in my two cents, just because. It's necromancy but hey why not?
The Author weighs in on the subject like he has a bias. Sirlin is good at his job, or he wouldn't be successful and I'm not out to discredit him, only out to suggest that maybe the same subject could have been tackled neutrally to better aid up and coming designers and game enthusiasts.
Sirlin says:
"Slippery slope is usually a bad property in a game"
This made me balk. Every game I've ever played extensively where I have noticed slippery slope, it has been a good, if not necessary thing. Sirlin is a smart guy so why does my gut say he is terribly wrong in this one instance?
So I thought about it a bit and realized what is going on here. Sirlin comes from a world of fighting games. The longest a fight lasts is a minute, maybe a minute and a half. Perpetual comeback is just fine within this context, in fact probably a necessary game design tool in order to make a fun game. In star craft, there is no clock, only an ever dwindling supply of resources. A game can last 7 minutes or it can last an hour. In order to keep the amount of time invested in a match reasonable, controlled slippery slope is not just necessary, it is the only game design tool that makes sense to bring a natural end to the match.
What I'm trying to point out is that slippery slope and perpetual come back are game design tools, nothing more. In the creation of a game, designers need to consider the experience they want to deliver and what end-game mechanic they want to employ to bring those goals to fruition. A game that has a 2 minute life span can allow unlimited ability to come back within that time frame, while a game that has no clock limit needs some method to create closure, or the game will just dwindle feebly with no satisfying conclusion for either side. This doesn't make one mechanic "usually bad" and the other usually good, it simply shows them for what they are, tools, tools that need a craftsman to apply them at the right time.
I disagree Mugulord, I think slippery slope really is generally bad. I also think it has nothing to do with me playing fighting games. I've played many, many kinds of games. You have it backwards anyway, because the shorter a game is, the less bad slippery slope is. Imagine playing some 9 hour game where the advantages from the first one minute of the game snowball over time to make the first one minute the only minute that really matters. That's not so much a "preference" as "a bad thing."
Slippery slope is also absolutely not the only tool to make a Starcraft game come to an end. Just think about how amazingly bold of a claim that is. You're saying you're familiar enough with the set of *all possible* techniques that anyone could ever dream up to use in an RTS that you can confidently say that NONE of them work except slippery slope. I mean seriously. All you have to do is disconnect the win condition with the can-play-the-game condition. You can also give players access to stronger and stronger attacks as the game goes on such that defense becomes less and less possible, encouraging some kind of ending. You can do a bunch of things that aren't endless slippery slope.
A bit of slippery slope can be ok, but any time it's making end games not matter, or end games not even *happen* because the game is usually conceded anti-climactically, that's pretty bad. Slippery slope that can actually be recovered from can be ok, like a knockdown in a fighting game (you don't get knocked down inside of other knockdowns, so there's a limit to how bad it can be, and later you return to neutral slope).