For Sans, use the W, A, S, and D keys to throw the SOUL around. Q summons a Gaster Blaster, and E summons Bones. For the SOUL, use the arrow keys to move, and M to select the FIGHT button. As Sans, every time you use a move (except bones) it needs a cooldown. You can only attack when your cooldown is at zero.
Sans, The SOUL, The FIGHT icon, and inspiration for this project by Toby Fox. I do not own anything in this project. You'll have to click the green flag a few times for it to work.