Toribash

Toribash is a physics-based fighting game, from Swedish developer Hampus Söderström (also known as "Hampa"). When you start a match, two mannequin-like figures (Tori, the attacker, and Uke, the defender) are placed facing each other. The idea is to control Tori and make him attack Uke, but here's where the tricky part comes in. Instead of having basic commands to move around, punch, kick and such, you have to control the actual muscles and joints of Tori's body!

You don't control Tori in real time. Instead, you carry out Tori's movements step-by-step. First, you select the muscles to move, then press space and (with the default settings) ten frames of time pass. Every ten frames, time stops for you to adjust Tori's movements.

You have a fairly basic set of muscles to control, and each muscle can be set to extend (move out), contract (move in), hold (remain rigid), or relax (remain loose). There's the neck, pectorals, shoulders, elbows, wrists, chest/waist, lumbar, abdomen, hips, glutes, knees and ankles. Since you can move Tori's body any way you want, there's no limit to the kinds moves you can make him do. The best part is, if you strike one of Uke's body parts with sufficient force, it breaks off, spraying copious amounts of blood all over the place.

The game also features a multiplayer mode where one person takes control of Uke and another of Tori. They are given a limited amount of time in which to simultaneously determine their moves before they are played out. Players receive points for damaging each other, and a player wins when the time runs out and they have the highest score or when any part of their opponent besides their hands or feet touches the ground. The game has a ludicrous number of mods that do everything from adding enormous swords (which, in their current iteration, are so heavy they just break your hand off at the start of the match) to disabling gripping.

There are four standard game mods that have official servers hosted for them. Judo, which is essentially the "standard" mod and has a high frequency of limb removal. Wushu, which is Judo where gravity is lower and players start far out of each others reach. Since walking is pretty much a physical impossibility due to moving 50 frames at a time, this necessitates complicated acrobatic maneuvers to cover the distance and attack. Aikido has a significantly higher gravity, limbs are harder to break and almost impossible to remove, and there is a little box around the players beyond which they lose if they touch the ground at all. Aikido also moves at 20 frames per move, rather than the other mods which move at 50 frames per move, making it an overall slower and more intricate match. And then there is Dual Swords, where each player has swords instead of hands. The swords instantly remove any body part they touch, and so attacking quickly is infinitely more important than hitting with strength.

Oh, and it's also free, and available at toribash.com.

This game provides examples of:

 * Ass Kicks You: Very possible in the wrestling modes.
 * Big Heroic Run: Curiously averted, as the joint-based engine makes it incredibly hard to consistently "run". There have been competitions and game modes centered around how long a player can stay upright.
 * Bullet Time: Not so much the ability to slow down time, but the way Tori's joints move around, and the level of gravity seem to suggest a form of slow-motion, almost like they're fighting underwater.
 * Car Fu: Gamemodes where you ride around on motorbikes and in cars.
 * Cherry Tapping: Due to its near-unlimited possibilities, anything you can think of. There is a (somewhat) popular move in Judo mode where you spend the first move ripping your own legs off to use them as stilts.
 * Combat Breakdown: Done with loss of limbs restricting movement, (Though they may still move independantly somehow)
 * Critical Existence Failure: Tori and Uke are 100% alive and functional until something besides a foot or a hand touches the ground, at which point they both go limp.
 * Dance Battler: There's a capoeira game mode, and many players battle like this.
 * Did You Just Punch Out Cthulhu: The infamous hampacock.rpl replay. The creator of the game, Hampus Söderström, faces off against another player. What proceeds is what many agree is one of the best in-game matches of all time, with the player finally tossing Hampa out over his head backwards using Hampa's own momentum. Hampa's reaction as he sails out of the ring? "cock."
 * Drunken Boxing: Due to the ragdoll nature of the game, most players resemble this.
 * Earn Your Happy Ending: Gaining entrance to any clan or group in the game is going to involve a lot of virtual pain.
 * One of the early clans, ToriGod, now has a relaxed invite-based entry system, but in the early-versions of the game, the only way to get in was to beat the members. One by one.
 * Game Mod: Encouraged. The game is .lua based, letting players script both in-game gamemode mods and add-ons. A player can, if they know their way around the language enough, create nearly anything. There's a mod competition monthly, and one mod (boxing, complete with ring and all) became so popular it became an official server.
 * Grievous Harm With a Body: The entire game is about using a body to beat up another in a literal sense, but the ability to THROW your own limbs to do damage is rather unique.
 * Hurricane Kick: Can be done, though rather difficult without altering the physics rules a little.
 * Launcher Move: Generally averted, but in wrestling modes it's not hard to lift your opponent into the air with the right leverage. In wushu, it's possible to send opponents flying with an upwards strike.
 * Ludicrous Gibs: Blood comes spurting out of any body part you break off. You can break each individual joint apart, too. Since they're just figures that look like mannequins, it's not that grotesque.
 * Made of Plasticine: In sword fights, a Tori's resistance to attacks is greatly reduced, to allow swords to sever limbs. However, this also means that a well executed kick can take an opponent apart. It's possible, if your opponent is not wise to the tactic, to execute a twin footed kick to the chest that causes your opponent's arms, legs, and head to be separated from the torso, and sends that torso flying out of the ring.
 * One Hit Kill: In earlier versions of the game, there was a brief spot in the abdomen, which, thanks to a bug, would gib mercilessly if hit hard enough. It's a small spot, but still one possible to hit in multiplayer rounds. In recent releases, the bug has been fixed, but the term boompunch refers to any attack that produces a similar effect.
 * Only a Flesh Wound: Losing a limb has no effect on the lifespan of Tori or Uke. In fact, if one of their dismembered arms manages to grab onto the other combatant it can throttle them with the stump.
 * Ragdoll Physics: You can relax all your fighter's muscles with a single button press. It also happens automatically when you lose a body part.
 * There's actually an outright style of fighting called "Relax Style", which is essentially leaving all body parts relaxed except the ones that you're actually using. It takes a lot of practice to pull off well, but leaves you able to counter almost any situation. It's not seen too often these days, though.
 * Sword Fight: Can be done with the correct game mode. There has been at least one instance of players having a sword fight with their own dismembered limbs as the swords.
 * There Is No Kill Like Overkill: In spades. Madman replays are especially popular, but the only way to qualify as one is to dismember at least FIVE of Uke's limbs.
 * Unstable Equilibrium: Subverted, depending on the player. Ripping another player in half may lead to him using his upper body to hold you down while his lower half autonomously jumps over to decapitate you. Body parts are also the game's only source of projectile weaponry.
 * Victory Pose: It's especially common to see these at the end of single player replays.
 * X Meets Y: The best way to describe this game is QWOP meets Mortal Kombat.