Mega Man X4 is an action platforming game and the fourth game in the Mega Max X series. Is the first game in the series to be brought to the PlayStation and takes advantage of its capabilities, from having more complex backgrounds to fully-animated cutscenes. Taking place many years after Mega Man X3, a Reploid military force called Repliforce was formed to help the Maverick Hunters suppress Maverick uprisings, but have quite an uneasy relationship with the human government. After the sabotage and crash of Sky Lagoon, some of Repliforce's troops have been suspiciously seen with the Maverick terrorists, causing accusations from the government to be thrown at them. This finally breaks Repliforce's relations with the government, and Replilforce starts a rebellion to break away and form their own Reploid-only nation. X and Zero have been tasked to stop them in hopes of preventing yet another long war.

For this run, HappyLee decides to input a code that gives them access to the Ultimate Armor, the best power-up in the game. Unlike the later games, it's not given to X at the start and must be retrieved from a Light Capsule. Nevertheless, HappyLee demonstrates how quickly the game can be beaten with the Ultimate Armor, doing some RNG manipulation here and there to reduce lag.