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Slippery
Slope and Perpetual Comeback
Even some of the very best strategy games
(chess and Starcraft, for example) suffer from slippery slope. That
means that once one player begins to lose by a little bit, he’s at
a disadvantage and likely to fall further and further behind. In
this type of game, one player usually loses long before the game is
technically over, which isn’t exactly fun.
When a player loses a piece in chess, his
ability to attack and to defend has been 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 affect. Clearly, losing a lot of pieces,
say 8, puts a player at a significant disadvantage. It’s pretty
hard to make a comeback in a chess game, and a chess game is usually
“won” for all intents and purposes many, many moves before the
actual checkmate move.
Starcraft is the same way. Consider two
Starcraft players of nearly equal skill. One player rushes the other
(sends a small attack force very early in the game). The rush forces
the defender to spend some time defending himself, and his worker
units are disrupted for just a few seconds. One worker unit is
killed, then the defender is barely able to defeat the attacker’s
units. This conflict was actually very close. It probably didn’t
feel devastating to the defender, but he’s just taken the first
step down a very slippery slope. The defender spent time managing
that battle that the attacker used to build a stronger economy. The
defender lost a few precious seconds of collecting resources, but
the attacker did not. The defender must spend both the time and
money to replace that lost worker, but the attacker does not.
Resource collecting is nearly exponential in Starcraft. A small
disadvantage early on becomes more and more magnified as the game
goes on.
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| The outcome of this
game of StarCraft was basically decided during this early
rush: Zerg will lose the game. |
Apart from the exponential nature of resources,
there’s the same concept of losing pieces as in chess. If an
attacker kills some of the defender’s units in Starcraft, the
defender is that much less able to defend or attack in the future.
If a defender barely holds of an attack, but comes out slightly on
the losing end, he’ll be even less able to defend against the next
wave of attacks that are sure to come moments later. He’ll then
probably fall further behind, and be even less able to stop yet
another attack wave. There basically aren’t comebacks in Starcraft.
And just as in chess, the moment of loss comes long before the
actual conditions of the game ending are fulfilled. As fun as
Starcraft is, this slippery slope aspect definitely detracts from
the experience.
Fighting games typically don’t suffer from
slippery slope. In Street Fighter, for example, your character still
has all his moves even when he’s about to lose. While it might be
“realistic” for a nearly dead character to limp, move slowly,
and have generally less effective moves, it sure wouldn’t be fun.
Comebacks are frequent in Street Fighter, and games often are
“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 version of Street Fighter 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. But back to our
story….
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| Lau (right) has Sarah
(left) at the edge of the ring. Another hit could result in
him ringing her out. |
Perpetual Comeback: Puzzle Fighter’s Claim to
Fame
Is there an opposite to slippery slope? A game
in which losing actually increases your chance to win, rather than
decreases it? It’s a strange concept, and I’ve dubbed it
“perpetual comeback.” In all the world, I’m aware of only one
game that truly uses it: Capcom’s Super Puzzle Fighter II Turbo,
or Puzzle Fighter, as it’s commonly referred to.
Puzzle Fighter is, in my opinion, far and away
the best puzzle game ever made, and even one of the best games ever
made. It looks 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. Sounds pretty standard, right?
Several factors come together to create
perpetual comeback in Puzzle Fighter. Firstly, each “character”
(there 10 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!
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| 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.
If you know of any other games that use
perpetual comeback, I’d love to hear about them. It’s a powerful
and dangerous concept that could very easily ruin a game, even
though it shines in Puzzle Fighter. It spurred me to design a puzzle
game based on Puzzle Fighter to capture the genius of perpetual
comeback. I’d also
enjoy designing perpetual comeback into other types of games—a
challenging notion indeed! Any thoughts, fellow designers?
Talk
back! Discuss this article in the forums.
|
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| "Sirlin
was Zerg. I beat him down." |
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| "MvC2.
Bah. Guard break into Cable's AHVB x 3 is too good." |
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| "Sirlin
thought he had me this time, but his Donovan sucks." |
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