UPDATE: After analyzing the game's error message and messing around with UndertaleModTool, I managed to fix the crash I was having on my own. I'm leaving the original upload up just in case this breaks something else, but if you get the same crash I had, you can use this build to get past the empty falling room and reach the final boss: https://www.mediafire.com/file/36a9zuotzb6pgtc/WilliU_1.1.5.0.√-1+crashfix+versi...