Z is enter, X is back, arrow keys to move shield when you are green soul, and to move when you are red soul. This is my attempt in recreating an Undertale fight as close as possible to the original fight, and i chose to recreate undyne because it is my third favorite fight, besides sans and Asriel Dreemur. I hope you enjoy it! Warning / bugs: When it is your turn, do NOT try to press Z when you have the ACT or ITEM buttons selected, because the aren't programmed in yet it will just make the game break, and you will have to press green flag to reset it.
Credit to Toby fox for making undertale. Coding / Animations done by me. Some sprites from KSH_15.