There as a black bar across the horizon and some textures flicker like glass and reeds. I made a bug report before and i was told to update my gpu drivers. Once i did this the issue fixed however the next day the issue started again. It seems if i want the game to run normally i need to re install my drivers every day. EDIT: I just did some tests and it appears that only worlds made in 28b and 29b have this issue but the problem then occurs in any version running that world.