Graphics are really messed up and there is a flashing white strobe light.

Put the summary of the bug you're having here

*What I expected to happen was the game to open normally.

*What actually happened was some major graphic errors. All blocks are flashing white and have washed out colors, water is just solid white from above, normal when swimming. Inventory images are all messed up. Mobs and villagers and animals are normal, as well as grass, crops, torches, etc.

It just happens whenever I try to load a world in the new snapshot.