Press Z To Select And X To Unselect Determination/red: WASD keys Black heart: Flipped keys Blue heart: Press W for jump Orange: move up down right left but you cant stop moving Celest: WASD but Slow movement Green: Disappeared/not in game :(
Credit to @eli567 for the Undertale battle engine you can change the music in backdrops Pro Tip: murcy might end the fight but also not Secret Pro Tip!: if you press z with mercy once you can attack him/scratch cat because he let his guard down :D