Rockman Exile is a Mega Man 2 ROM hack that makes the game even harder than it already is. Witness as lights in stages periodically go out, boss stages that are fought in the dark, more enemies present on-screen that shoot even more deadly projectiles at you, and more! Aside from the super hard difficulty, there is also additional music that appears to have came from the Mega Man Game Boy games and other games outside of Mega Man.
cui goes through the romhack and uses a combination of glitches and damage boosts to beat the game as fast as possible.