Nice.
Bugs:
1: In Warp Zone->Twists and Turns, the leftmost wall is one pixel off (the higher one is one pixel more wide than the bottom)
2: In Warp Zone->Trouble-U, the upper floor is a pixel off, the right is one pixel higher than the left
3: In Warp Zone->Giant Maze, at the bottom floor, you can go left and become stuck in the wall because the right has a block in the way.
4: In Intermission 1->The Polar Dimension Returns, the enemies is a bit glitchy
5: In Intermission 1->Angel Falls, flipping at the top, aside from being a shortcut, gets you stuck in the wall at the bottom. For some reason, the usual "getting stuck in the wall" action didn't happen, and Viridian just went through it as it was air. Weird, but... yeah, should be fixed anyway.
Also just a hint: one-way-walls glitch sometimes. Nothing bad happened the way you used it in the polar dimension, but just so you know.
Another hint: map(off) (the map is still logged however)
If you like, I can also fix the intermission background (just takes a few minutes of my time :p)