So I recently started playing Isaac again and decided to play with this mod because it looked fun. Tbh my PC is pretty low tear but it's strong enough to run the game smooth 60 FPS at all times. However when I install the mod my FPS on normal floors goes to 58-59. This isn't the problem though.. When I go to the Glacier and Tomb floors my FPS gets terrible. It goes down to 40 sometimes even under 30. I have tried turning off V-sync but it doesn't help. I've tried installing mods that help with fps (removing gore etc.) still no difference. I'm thinking it's probably my PC since as I said it's pretty old but I'm posting this just in case someone had the same problem and got it fixed.