Playing with the latest wip build v0.9.6-713-gde0aca4
Unless you change to Frameskip 1 (which pretty much ruins the game) the top half will keep flickering.
Switching between CPU and GPU render mode doesn't make a difference either.
But I noticed that it doesn't start flickering as long as you don't switch from window to fullscreen or fullscreen to window mode during the game.
I don't remember having the same problem with an older build.
Unless you change to Frameskip 1 (which pretty much ruins the game) the top half will keep flickering.
Switching between CPU and GPU render mode doesn't make a difference either.
But I noticed that it doesn't start flickering as long as you don't switch from window to fullscreen or fullscreen to window mode during the game.
I don't remember having the same problem with an older build.