An early combo. Jumping heavy kick, into crouching medium kick, into Hadouken.
Combos are a trope of video games. They are a sequence of hits where, if the first hit connects, the target cannot act in any capacity until it is over (compare to Mercy Invincibility). A Combo Breaker is the sole exception to this rule. If your target could have escaped your attack sequence by any other means, such as blocking or performing an invincible move, then it isn't a combo.
Generally these show up in Fighting Games, but they can also be seen in other genres. For combos to be possible, attacks in a given game must put the enemy in a state where they cannot act (fighting games refer to this as "hitstun"). The state must also be vulnerable, and the attacker must recover from their attack fast enough to deliver another before the state ends.
Knocking an opponent down can end a combo due to the potentially gained invincibility, but not always! Some games have moves that can be used on downed opponents, and knock-downs due to effects of being dizzy actually set the opponent up for further punishment.
A gauge will often be present, especially in fighting games, that will keep track of successfully combo'd hits. When the combo meter reaches a high number, you have Idiosyncratic Combo Levels, and may receive some entertaining messages underneath.
Very much Truth in Television for martial arts, as fighters will train to deliver a series of moves which are easy to do in succession, maintaining momentum while preventing the opponent from recovering.
If two or more attacks are done in concert or simultaneously, but do not fulfill the above criteria, it isn't a combo, but may be considered a Combination Attack.
Commands for special moves are not combos (eg. down, diagonal, toward + punch).
Combo is a term that can be used loosely out in the wild; many uses of the word likely do not fit on this article (but perhaps on the Combination Attack article). However, feel free to add parodies or other examples that contain some aspects of combos (just be sure to label them as such). Rhythm game chains and puzzle game chains are not combos, nor are the combination attacks found in Chrono Trigger.
Ur Examples of combos show up in some beat 'em up games. One example is Golden Axe, where repeatedly pressing the attack button can result in a pre-canned combo where the enemy is driven to their knees as the player character bashes them over the head with pommel strikes followed by a kick.
While playtesting Street Fighter II, the developers discovered a glitch, later dubbed "canceling", where inputting the command for a special move would interrupt the recovery of a normal move that connected. The glitch was kept in as the developers thought it would be an interesting "feature" for players to find, but nothing exceptional beyond an easter egg. Players and publications quickly caught onto these and spread the word. By the time Super Street Fighter II came around, the game was actively counting the hits of each combo.
Rapid fire punches and kicks, as well as late jumping attacks into normal moves, are also combos in Street Fighter II. Canceling may be a glitch, but these are likely intentional.
Darkstalkers was the pioneer of zigzag chaining, where players can chain normals from weakest to strongest, tracing a zigzag line with the button presses, making this series a grandfather to the Marvel series, Guilty Gear, Melty Blood and countless doujin fighters.
Killer Instinct was the first game to use its specially designed combo system as a selling point, and after it took off, virtually every game had it's own unique combo system built in. Killer Instinct's system was notable for having automatic combos launched by Button Mashing, and for the game's announcer enthusiastically announcing when a player managed to launch an extremely long "ULTRA COMBOOOOOOO!"KI also created the "C-C-C-Combo Breaker!", which infests imageboards to this day.
Killer Instinct 2 had a great deal of refinement put into its combo engine, to the point where button mashing would do very little but sixty+ hit combos were achievable without glitching.
The announcer in Mace The Dark Age will criticize the player for making a combo longer than ten hits, using such words as "excessive" and "obnoxious".
Every Tekken character from the beginning of the series has had a 10-hit combo deliberately programmed in. When the Tekken character Heihachi appeared in Soul Calibur II, he had three moves that were just called "10-Hit Combo."
Tekken's versions aren't usually actual combos though, meaning that you can block or evade somewhere in the middle of them even if you're hit by the very first hit.
Tekken's combos usually come in air juggles where the first hit pops you up in the air.
In fact, you can generally find out which characters are far and away the strongest by looking at the combos that don't do this. Characters such as Heihachi or Steve Fox have had great combos that do not require a "launching hit" to guarantee the rest of the combo, and as such have been considered top-tier at times, especially the fifth installment.
Satirized in the animated series Drawn Together, in which the character of Xandir has a number of absurd power-ups and combos, mostly playing on the fact that Xandir is gay (e.g., a special attack called 'The Reach-Around', etc.)
The side-scrolling action RPG Legend of Mana has a fairly complex combo system, which rewards you with healing items if you make a long enough combo of attacks.
Unfortunately, simply tapping the attack button at a specific rate will give an easy infinite combo, circumventing any need to play with the system present.
Drakengard rewards combos with healing items as well, though at fairly arbitrary numbers. (The first one is seventeen hits.) If the character is at full health, the reward is instead an orb that lets out a shockwave when touched, sending all enemies in range flying; the resultant hits add to the combo. After about 100 or so hits, the reward is always a black orb that gives temporary Quad Damage.
Every Tales game lets characters combo beyond their basic attack sequence by chaining skills together, offering bonus experience among other things for players who can cooperate to make extended hit chains. Symphonia gave a title to anyone who pulled off the most basic combo in the game (Lloyd's hit combo into Majinken) as well as an additional string of titles for ever-mounting comboes (up to 100 hits). Tales Of Destiny Remake and Tales Of Innocence have battle systems geared around comboes - any Innocence character can generally get to at least 20 or 30 hits on their own by endgame, and the AI tends to be very helpful in driving the number into the hundreds against some bosses.
The Tales mantra, for those curious, applies to all games except Destiny Remake, Hearts, and Graces, which used the separate CC/EG gauge, and runs like this: "Attack, attack, attack, tokugi/base, ougi/arcane." Insert extra attacks and tech tiers where applicable.
Tales Of Vesperia has taken this to ridiculous degrees. Overlimit in Vesperia allows you to chain physical attacks and cast spells instantly for as long as it's active. Combining this with certain skills allows main character Yuri to preform infinite combos. Also, equipping the right skills to Rita, the main spellcaster in your party, allows her to chain magic spells together.
TODR uses a Combo Capacity system that allows you to combo for as long as you want until either your CC runs out or the enemy escapes the chain (it regenerates pretty fast). The CC system was also used for Tales Of Graces, Keroro RPG, and, in the form of the hybridized EG system, Tales Of Hearts.
In The World Ends With You, reaching combo benchmarks is one of the conditions that ups your "special" experience multiplier.
Exists in the game Fable I under the name "Combat Multiplier" and the higher it is, the more experience obtained when you beat an enemy. However, getting hit rounds it down to the next-lowest 5.
The Mana Shield spell turns this into a Game Breaker in that it allows you to take blows without penalty to your combo. Find an area with unlimited monster spawn (eg Grey House), activate the shield, and it's not too difficult to get the meter above 300 or so (at about which time you might as well stop, 'cause your experience counter just maxed out...).
Eternal Fighter Zero has the Reinforce gauge, which can be used to cancel almost any attack and gives you a small window to input the next command, leading to all sorts of possibilities for creating combos.
The PS2Fist of the North Star fighting game by Arc System Works is, basically, a combo maniac's festival. Comobos of up to thirty-three hits have appeared in tournaments. It helps that each character has an attack whose sole purpose is to launch the enemy into the wall, leaving them open for such tactics.
Also from Arc is Guilty Gear, which is MADE of combos, so much so that the damage scaling system is visible for the players' convenience, as well as fast to kick into high gear to stop Dust loops from being instantly fatal.
Devil May Cry 3 lets you feel like a superhero by the simple measure of allowing you to cancel out almost any move into almost any move at no cost, racking up devilishly large combos limited only by the monster's ability to absorb damage. In most games, this would break the game right in half. In Devil May Cry 3, it was a necessity.
Art Of Fighting 3 uses combo moves known as "Command Attacks" which the characters do 3D fighter style combination attacks. Although many of the other SNK games have 2D fighter style combs that can be implemented.
Ragnarok Online two martial artist classes, the monk and the Taekwon has combo moves, the monk must charge up his spirit orbs in order to unleash something beyond the 3 hit comboo to follow it with deadlier blows but can only land up to 10 hits with a full skill set in his trascended class. The Tae Kwon is more traditional with him preparing kicks and pressing the skill when he can use it.
Then of course there are Taekwon Rankers, the 10 best Taekwons (sorta) on the server gaining the ability to - when he can get in a kick - make infinite kicking comboes limited only to the mana pool of the Taekwon. A kick is 2 sp, a normal Taekwon has ~2-300 max. mana.
The Super Smash Bros. series has these as well, though Brawl has very few due to physics changes intentionally made to remove them.
Kingdom Hearts games allow you to string attacks together (abilities let you extend the combos to a preset number), after which you can pull off a finishing move which does extra damage.
In the sequel, Combo Finishers are one of the only ways to finish off bosses. (The other ways being Limit Breaks and Magic). If Sora/Roxas doesn't perform a combo on the boss, it will continue to retain it's last hit point indefinitely. (It should be noted that party members, and playable guest characters like Mickey and Riku cannot perform combo finishers. Only Sora can. Because he's apparently the only one allowed to kill the bosses.
It should also be noted that Sora himself has a fairly lengthy hitstun, and is thus easy to combo; thankfully, few enemies take advantage of this. Also, on boss characters, if you choose to temporarily forgo your finishing move (meaning you now have an infinite combo attack), they will always block/teleport after a little while, to avoid allowing a completely cheap win. Works perfectly on non-bosses, though.
The PSP Star Ocean games, First Departure and Second Evolution, automatically string attacks in a set of three; if the first hits, the rest can't be blocked. However, you're more vulnerable after a combo than after a single attack.
And let's not forget that the 3rd game Till The End of Time also had a combo system which encourage you to pile on the hits in order to activate the Bonus Gauge and take advantage to it. If you wanted to get particular bonuses (Triple EXP and Double Fol), doing combos was the way to go and you'd grind quicker if you were lucky enough to get the Triple EXP bonus. On top of that, you gain Battle Trophies depending how long a combo you managed to reach. Combinations with the charcters' special attacks can make such combos possible against meaty enemies with lots of HP.
In the anime CLANNAD, Tomoyo has a trademark rapid fire sequence of kicks that juggles her opponent in the air, and a combo meter actually appears every time she uses it (on Sunohara). At one point, she and Tomoya do a chain combo that bumps the meter to over 1000 hits. In the Visual Novel, she chain combos with almost everyone on the cast.
Gothic I/II allows melee specialists to chain multiple weapon swings together with properly timed presses of the "attack" key, instead of slower normal attacks.
Likewise, The Witcher allows you to chain together multiple sword attacks by timing them carefully. The maximum chain length can be extended by developing corresponding sword style skills.
Batman Arkham Asylum uses this extensively. You get vastly more experience for racking up a combo, and even more for a combo that uses all of your different moves. During several of the combat challenges going for large combo's is pretty much the only way to get 3 medals.
Ninety Nine Nights has a system where the higher your number of combos, the more likely a Mook will drop a rare(r) item (i.e. dropping a lvl 4 item instead of a level 1 item). And just to make things easier for you, each character has at least one stage where you will face a very large number (getting close and probably surpassing the 1000 range) of Mooks at once.
Tatsunoko Vs Capcom actually encourages smaller combos due to its damage scaling (which triggers pretty quickly). Expect to hear "YES!" (the game's call-out to three-or-four-hit combos) a lot.
Juggle combos. Love them? Hate them? Either way, Mortal Kombat is their progenitor. Juggle-centric games like Marvel VS Capcom have this series to thank.
In Duel Savior Destiny there's a small meter with several boxes on the bottom of the screen. The higher level you are, the more boxes there are. While the blue half of the meter gets filled up over time when you aren't blocking, the red one fills up as you launch attacks and overwrites the blue side. When you've filled up two red boxes you can then launch a super.
Magna Carta 2 has something like this. Your attacks get more powerful, which builds up Kan. After a while, you have enough Kan to perform a skill, which can then go into Overdrive mode, another skill, a Chain state with the next character, and then even more skills in Chain Drive mode.
Prince of Persia (2008) has a wide variety of short combos that can be chained into longer ones, building brick-style. The longest combo in the game contains all four available moves over fourteen consecutive strikes. You get an achievement for actually pulling that last one off (the biggest problem being that most enemies run out of health half-way through it).