This is the harder version of "Undertale Physics" by StephenTheCoder. I hope you enjoy! Instructions: Arrows to move. Space to change hearts. F for attack (way more attackers!). H for heal. B to change box size. (New stuff) X to get rid of the box. Z to bring it back. less blue heart glitches! Bones one hit kill you! (If you want less of a challenge, get rid of the added blasters.
Credits to Toby (Radiation) Fox for providing Undertale Credits to StephenTheCoder for the Original! Check it out below.