Sometimes the game runs in slow motion if I increase the resolution. I have a GTX 770.
Super Potato Bruh runs entirely on the CPU in a lot of cases. Although I’m a bit surprised that it couldn’t use your GTX 770. It’s able to make use of my GTX 1060.
The resolution the game is set to before fullscreening affects how things look and run. The highest resolution doesn’t always look the best for whatever reason, so I recommend messing around with it. You should be able to run it fullscreen if you set it to the lowest (or second lowest) resolution before fullscreening.