It's Deltarune but if it was Toby Fox's bad fur day Halloween Hack of '08. While it doesn't have slurs by a mad grieving scientist, it adapts Deltarune Chapter 1 insanely well and I personally love how the soundtrack turned on! 

I played mostly on PC using the SNES9X emulator , but did try playing on a modded Nintendo New 3DS using a injection. Both worked as intended, though you need to make sure you have the specific rom they mentioned, my .sfc dump of the original game seems to be incredibly buggy when patched so I had to redump it into another format.