It’s a problem on the PC version too, but it’s more bearable than on the web version. One optimization that can be done quickly right now would be to disable the text popup while Demon Time is active. That might save some frames.
Viewing post in Update 0.5.0 - First Year Update comments
I did some tests and found that Demon Time doesn’t really affect FPS when idling. Its impact is only noticeable when a node is completed quickly, so it’s either some inefficient code running on node completion or the number of text popup gameobjects required exceeds the pool size, causing the game to instantiate them rapidly. The latter is much easier and safer to fix for now.