When you change the shader called 'Flip', the screen shows the environment as black, but all of the GUI's look perfectly normal
What I expected to happen was...:
The 'flip' shader would be displayed (where the screen is displayed upside down)

What actually happened was...:
The minecraft world went completely black, regardless of the time etc. and the hotbar stayed at the bottom of the screen instead of the flipping upside down and going to the top. This happened regardless of the gamemode and the hand/item was also black.

Steps to Reproduce:
1. Open any world or join any server on the 14w05a snapshot
2. Click on the 'super secret settings' button until the 'flip' shader is displayed
3. The world will be completely black