itch.io

you can try deleting the task in the background using the task manager. it works well for me. Another is the game mode ( if you have it ) it's windows + g, though if your pc is outoutdated it probably doesn't have that. close all apps except this. it'll improve the fps. 

if u have a laptop there should be an option in the settings for battery power and another one that is related to performance( I can't find it Right now since I'm too lazy ). 

P.S if u have a laptop and it's overheating try having a small standfan pointed at where the it's overheating. works well for me.