Screenshot of the game.
Pro-Pain! is a video game from the King of the Hill episode, "Grand Theft Arlen." The game is an obvious parody video game of the Rockstar game series, "Grand Theft Auto". It is created by several college students which are providing an "Active Electronic Lifestyles" course at Tom Landry Middle School. The students become enamoured with Hank Hill's life as a propane salesman and create a game to emulate him and his life in Arlen, Texas.
Mechanics
Being a parody of the real-life video game series Grand Theft Auto, Pro-Pain! has most of the game's mechanics. The game is a RolePlaying type with an open world, weapons, NPCs, singleplayer, multiplayer, controller support, and a leveling system. The main (and only) playable character is Hank himself, whom increasingly gets more buff as the character levels up.
As a third person shooter, Pro-Pain! has propane tanks as the main weapon in the form of throwing it, which it combusts and causes an explosion on impact. Players on the game throw these at each other, causing said explosion, which Hank rightly says does not happen. Despite propane tanks being the centric weapon, there appears to be a variety of guns available as well, including a flamethrower. There also appears to be a "Pimp Cup" as a melee weapon.
The leveling system is as a progression through the ranks of the propane industry as shown in the show, with the highest being an exclusive "Commissioner" mode.
History
Initially when it was released, Hank is tasked by Buck Strickland to investigate the potential impact it may have upon Strickland Propane and other trademarks or terms which Buck has, or has intended to own, as it references his company and Hank directly.
Hank, after discovering that the main character, himself, can be promoted, becomes uncharacteristically addicted to the game on the singleplayer option before finally discovering the online multiplayer via Bill Dauterive. Bill himself uses the game as a form of escapism insofar as it emulates Hank's life, which makes him a natural target for the more aggressive players on the game, which include Bobby's classmate, Dooley.
Buck discovers that the game is released in the Public Domain, and as such, does not constitute any legal infringement on his copyrights, but Hank continues to play the game at work and at home.
Hank raises his rank and experience, but is eventually defeated by Peggy, who is made "Commissioner" by the game creators. Peggy's character was designed to close the whole gaming network upon the character's death, which was caused by Peggy herself. Once Peggy's character "PQSmooth" explodes, the entire game ends and Hank is freed from his "addiction".
References are made which poke fun at the "Grand Theft Auto" franchise, with a specific weapon being a "Pimp Cup", which Hank uses to slap Peggy's character when his various other weapons cause no damage.
The game has not been mentioned nor shown ever since its debut episode, as Peggy had closed down the entire gaming network, presumably meaning the entirety of the game too.