Go into A Jump Too Far, go forward, and turn left to the eye. Stare at the wall, then proceed 
through Running Into Trouble by walking on the bridge. As the entity in the middle of this room
gets excited with movement, it will disintegrate the bridge. Then in The Ground Floor, collect 
the two blue blocks. Backtrack to the beginning (at the door labeled "The End"), then utilize 
the red gun's block-multiplying and mass-painting abilities to paint from the floor up a wall 
to meet with the other red blocks. You will then be taken into the finale, which mostly involves
transferring blocks in various areas.