Designing combo mechanics that make everyone happy

Combos are a huge part of the traditional fighting game. After accidentally being introduced in Street Fighter II, nearly every fighting game since has had some form of combo system. But as developers strived to create bigger and better combo mechanics that make the player feel more awesome, they sometimes forget about the equally important second player, and in some cases decrease interest from spectators. Combos can affect everyone, and anyone involved should be able to enjoy a combo.

In a fighting game, a combo is a series of attacks executed by an attacking player that are quick enough to hit the opponent before he can recover from the blow of the previous hits. A combo mechanic is a rule that controls when and how the player is allowed to do such combos. Many games have different combo mechanics. Most fighting games have a "canceling" system, where you can cancel the animation of an attack before it finishes, and immediately start a new attack. For example, one of Ryu's staple combos in Street Fighter is a low forward kick, canceled into a hadouken. By executing the input for the hadouken as soon as the low kick hits, Ryu will immediately cancel the recovery animation of the low kick and throw a fireball before the opponent has recovered from the low kick.

Many games have different rules for canceling systems. In Street Fighter, most normal attacks can only be canceled into special attacks. In Guilty Gear, normal attacks can also be canceled into other, usually stronger normal attacks. In Melty Blood, even hard hitting attacks can be canceled into weak attacks, which leads to a very flexible combo system. There are also more intricate mechanics, such as counter hit combos, or crouching hit combos.

When designing combo mechanics, there are three parties you must appeal to: Player one, player two, and the spectator(s). Each one gets something different out of a combo.


The first player

Player one (for the purposes of helping you visualize this later) is the player performing the combo. To this player, what makes a combo enjoyable is power. Anything from a light bread-and-butter combo, to a heavy corner only 100% counter hit combo must feel strong.

But what makes a combo feel strong to a player? It's knowing you did the right combo for the job. If every character only had one or two combos, then nothing would feel strong to the player. They're using the same answer for each problem. When a character has many ways to combo and punish mistakes from player two, picking the the most effective combo available makes the player feel stronger, because they did the smart thing. It's not the combo itself that creates the feeling of power, but choosing the right combo will.

Length does not necessarily make a combo feel powerful. In Street Fighter II, people ooh and ahh over three or four hit combos that last about two seconds, because they are powerful. But in a game like Guilty Gear, a strong combo can be over 20 hits, but people can get excited from them just as easily as SF2's relatively short combos.

But none of this means long combos are inherently bad. What is bad is when a combo goes on longer than it should. It's sometimes okay for a combo to be long if it truly deserves to be that long, but there are only a few cases where a combo should be allowed to continue.


The "action counting" system

The action counting system (special thanks to Sheep for the name) is my method of examining combos to determine how much the player is thinking. Instead of counting the number of hits in the combo, you instead count the number of choices the first player is making and the number of situations the player is taking advantage of. For each one, a point is added to the counter. The higher the action counter is, the more interesting the combo is. The lower, the more basic. It's fair to say the the length of the combo should be about proportional to the action count of the combo.

What qualifies as an "action" is usually one of two things.

• You are making a choice between two or more outcomes. Finishing a combo with a move that leaves your opponent close to you, versus a move that leaves them far away, but does more damage, is an example. Deciding to use a super attack for more damage now, or save it for an alpha counter move later is another.

• You are taking advantage of a situation or prerequisite. This ranges from anything to corner combos, to the opponent deciding not to burst. Counter hit combos, close range combos, having charged a move before the combo, being in a certain stance that allows you to combo differently, etc.

What does not qualify is simply pressing the next button in a combo when there is no other choice to continue. If the combo is A -> B -> C, pressing B after A and C after B is not qualified as an action, assuming A B C is the only combo available to the player. If A -> B-> D is a different combo with a different effect, then choosing D over C would count as an action, because the player is thinking about something. But in most cases, you're pressing the next button because that's just how the combo goes. Having these "combo fillers" aren't inherently bad, but if the player is completing an entire combo without making any choices after the first hit, there could be something going horribly wrong. The player might as well die in one attack to save everyone the time.

Now I will be the first to tell you that fighting games aren't math, and this system doesn't 'solve' fighting games, but using this system is useful for understanding where the player is thinking about his combo instead of just recalling a series of button presses without thinking about the opponent.

Let's examine two combos using action counting. Both combos are from the same character, from the same game and about the same length. (Megaman Volnutt, of Tatsunoko vs Capcom.) TvC is a good place for this since many combos vary in "action points" and length.



This is a "3-point" action combo.
- Started with arm attachment, allowing slightly more damage.
- Used super meter at the end to charge his fireball and gain distance. (The combo itself builds enough meter for this super, so it is not required to have any meter before the combo)
- Opponent did not burst. (Because he's a training dummy)

20 seconds is quite a bit for a 3-point combo. Let's look at something a little more advanced.


This is a 7-point combo.
- Corner combo
- Buster cannon must be charged about 50% before starting the combo
- Must have around 3 super meters stocked before the combo starts. (rare to have in TvC)
- Arm attachment used first to combo into the fully charged buster shot, due to its massive hitstun.
- Level 3 hyper combo used.
- Level 1 hyper combo used after.
- Opponent did not burst (Again, dummy. But in a real match anyone would burst out of that combo. More on that later)

For 25 seconds, it's just about worth it. With so many requirements for this combo, it's rare to just have the opportunity. But when the first player sees that opportunity and takes it, he probably feels pretty happy.

Some actions are more valuable or rewarding than others, such as using a Level 3 Hyper attack instead of a Level 1. While it is important that there are viable choices for a player to make in a combo, the choices feel less significant if the differences between two choices aren't notable. If the difference between combo A and combo B is 2% extra points of damage, the choice between the two isn't as interesting or even noticeable. What is ultimately important is the first player is making interesting decisions throughout the entire match, in or outside of a combo.


The second player

Anyone who's been hit by a ridiculously long combo knows that it isn't fun to sit and wait for the combo to be over. You're essentially in "time-out," while the first player plays the game and you get juggled in the corner to think about what you've done. To make the second player at least not feel miserable, give them some degree of control when being hit by a combo.

Games do this in different ways. In Super Smash Bros., you can use directional influence to move your character out of a combo while you're being hit. In Melty Blood, you can time button presses with your opponents attack to take less damage. In Guilty Gear, (and many other similar games) you have the option to burst. A get out of jail free card that immediately pushes your opponent off of you, stopping the combo. Simply having a burst can limit what the first player will do to the second player.

When the second player has no burst, the first player has no fear to throw every resource they have into their next combo, because none of it will go to waste. For example, in Tatsunoko vs Cacpom, player one could activate his Baroque cancel to do extra damage, and cause player two to gain less meter. But if player two had a burst, he could choose to wait for player one to activate Baroque before bursting instead of bursting immediately, causing player one to lose a valuable tool. It's things like these that give the second player choices even when they're being juggled in the air, which the first player must take into account.

But of course, if you have no bursts ready, you could find yourself in a combo like this.


That combo, by the way, is worth 9 points.
- Must start with around 3 meters stocked
- Must be close to the corner
- Used a burst to push Karas to the corner.
- Used a baroque cancel
- Used Ryu assist
- Used a level 1 hyper
- DHC'd into Ryu's level 1.
- DHC'd back into Casshern's level 1.
- Opponent did not have meter to burst (The most important part)


The spectator

Before anyone plays a new fighting game, they usually watch it first. For spectators to gain any interest in your fighting game, it has to be entertaining to a spectator, but also seem interesting to them as a potential player.

The spectator can be a tricky person to please. Some developers put the spectator high on the priority list of people to appeal, and add features to the game that interest spectators, but might inconvenience the players. Such as long and repetitive finishing moves, like Street Fighter IV's ultra combos, which lose their novelty very quickly. Sometimes the developer focuses too much on the players and not on the spectators, which create games that are great to play, but horrible to watch.

There are three major rules that should be followed when designing combos for spectators. They are all partially related to each other, but they can not do without the others.

• Style. Combos need to be fun to look at, or else people will be less likely to look at them. This is pretty obvious and probably the most important.

• Power must be conveyed. If a combo is the best the character has in his arsenal, it better look like it. A common bread and butter combo can not look like the most amazing thing in the world. Conversely, a character's most powerful combo should be the most spectacular.

• The combo's power is proportional to its rarity. Variety is the spice of life and video games. If a strong combo is too common, too easy to land and frequently used, its sense of power is lost. Even the most entertaining and powerful combos can grow stale if you've seen it too many times in a match. It's one thing for the second player to wait for a long combo to be over to continue player again, but it's a whole new level when the spectator feels like they're waiting for the game to continue during a combo. Street Fighter IV Abel's ultra combos are a huge culprit, since he can land that ultra extremely easily every single round, along with many other characters who seem to overuse their ultra combo.

"Insanity level"

All fighting games are different when it comes to combos. They range from the quick and short combos of Street Fighter II, to the infinitely long combos of Marvel vs Capcom. However, combos that might be okay in one game might not be in another. A 10 hit combo in Guilty Gear would look like a broken over powered combo in Super Turbo. But in Guilty Gear, no one would complain about a combo that short.

This has to do with what I call the game's "Insanity level." It's not usually something the designers have in mind when they make their fighting game, but rather something that just occurs. It's very simple, games where long combos are common get high insanity levels, and games with common relatively short combos are low level. Games like Street Fighter II have low insanity levels since most of them time you only land single hit attacks without comboing at all. Games like Marvel vs Capcom 2 and Hokuto no Ken reach the highest levels of insanity, because as they say, one touch will kill you every time.

Marvel 2, despite having ludicrously long combos that would otherwise be too much in any other fighting game, remains an entertaining and deep competitive game that many players still enjoy. This is because the players and the audience accept the game's insanity level. This is mainly an issue of preference. Some fighting game players love the simple yet highly strategic elements of old school fighting games, while some prefer the high action and high flying aspects of new school fighting games, and some players (like me) enjoy both.


Conclusions

To put it as simple as possible, player one needs choice to feel powerful, player two needs control to not be bored, and the spectators simply need to have an interesting fight conveyed to them in a visual way they can understand. They are not strict rules, and allow a lot of flexibility. Anything from a ground based footsie oriented 2D fighter, even up to an insanely fast air based 3D fighter can follow these rules and make people happy. What is ultimately important is that there is always a fight going on between the two players. Both players should always be taking the other player's actions into account. When a combo starts, usually the fight is put on hold. The first player plays a one player game of hit the correct buttons in order, and the second player merely waits. This isn't always horrible, especially if the combo is under five seconds or so, but even if you're stuck in a 20 second long combo, you can still be fighting.