What I expected to happen was:
The game to run smoothly and affectively.

What actually happened was:
Colors flash across the screen wildly, sprites flash different sprites than what they should be, sometimes the buttons on the pause menu half disappear (but the text stays).

How to recreate the issue:
Playing the game within a minute or two, you would be able to have experienced enough of this.

I've tried uninstalling and reinstalling the game. It's been doing this ever since I played 1.8 for the first time.

Thank you so much for your time!