Thrill Kill

The gameplay consists of up to four opponents in a closed 3D room fighting to kill one another one-by-one using gory special moves known as "Thrill Kills". The four attack buttons correspond to each character's arms and legs, while attacks are blocked by standing still or by holding down the guard button. Double tapping in any direction allows players to dash. Each character has four throws, including a "Swap Throw", which causes the player who performs it and the opponent to switch places, and a "Hold Throw", which pins opponents down in front of the character that performs it. Characters can also perform both high and low counter hits.

Instead of the usual life bar, characters have a "kill meter" that increases with each successful attack performed. Whichever character fills this meter first must use a Thrill Kill on one other opponent of their choice, which kills them and removes them from the round. The manner of the kill depends on the button input upon grabbing the other character. The round then repeats without the defeated character, with the character who performed a Thrill Kill in the prior round earning a small boost to their kill meter at the start of the round. This continues until there are two fighters left, and whichever fighter's kill meter fills up first wins, triggering a final, character-specific death animation.

In the late 1990s, Paradox Development began development on a PlayStation game titled Earth Monster, a fantasy sports game based on the Mesoamerican ballgame where players would control large, muscular Aztec warriors who punched and kicked one another while trying to get a ball into a hoop. The game's publisher, Virgin Interactive, repeatedly encouraged the developers to make the fighting aspect more violent, before eventually deciding to turn the project entirely into a fighting game. Its Aztec aesthetic was soon replaced by one inspired by BDSM and intended by Virgin to cause controversy, which they hoped would help it sell better. Harvard Bonin, the producer assigned to Thrill Kill, showed developers fetish magazines, such as Skin Two, and BDSM DVDs as references for the desired art direction. The game was originally announced under the title S&M.

Designed as an especially violent, "full-blown adult" fighting game and the first four-player 3D fighting game, Thrill Kill was meant to compare to the similarly violent Mortal Kombat series. Paradox hoped that the game's success would help the studio earn mainstream recognition. The plot of Thrill Kill, based around each of the characters fighting for a chance at resurrection after being sent to Hell, was written by the game's assistant producer, Brian Gomez, and inspired by the musical Cats. Moves were given names such as "Bitch Slap", "Swallow This", "Crotch Crush", and "Miner 69er", and several were designed to resemble sexual acts.

In a review of the beta version of Thrill Kill, Gamers' Republic's Mike Griffin wrote, "[Thrill Kill is] perfect for mindless fun with friends and cold drinks. Mindless, but not brainless. There should be enough depth to the gameplay to satisfy hard-core 3D fighting fans once Paradox has completed its final few months of dedicated beta tweaking." Griffin also stated, "There are a few bugs right now that prevent Thrill Kill from being completely effective."

Also reviewing the game's beta version, IGN's Jeff Chen wrote, "The action at this point is somewhat stiff, but it's still early, and if you're looking for blood and guts, this has got more than we'd ever imagined. We can't wait."