Some more things:

Turn Event
Changes the level by tilting it # Degrees clockwise/counter-clockwise, effectively "changing" the gravity.

Bubba Boss Fix
When boss is defeated, he turns into an angel and flies off the level (sprites are in JJ2, I checked.)

*.OGG File Usage
Allows Ogg Vorbis files to be played as music. (Not wav/mp3 because OGG is a lot smaller)

Episode Selection Screen
Makes it so when you have more than # episodes, they shrink to 40% size, and line up next to eachother. Main reason of this would be to prevent people from getting so worked up about *.j2e files with level packs.

Also, it would be good if custom episodes were always put AFTER the official ones.