itch.io

I also have issues with some games lagging and stuttering after playing for long periods of time. Most of the time saving, exiting them game, and then relaunching helps. I'm fairly certain that my issue in particular is with old RAM, and the cache memory not being cleared appropriately.

Yeah, it's the frame rate. These aren't frames like FPS frames, these are dozens of individual image frames at 1920x1080, being flashed on your screen very fast (60 images in a second) so if your computer can't store all those images, it will lag.

Most other animations are in 24 frames, so it's much less data to store, and isn't being flashed as fast on screen.