Check the undersides of your wraps. I found at least one place (the first wrapped ledge of the level) where if you fly against the underside of the cliff you hit a gap offscreen and glitch through.
In the room with the propeller block you can use the propeller block to get onto the ceiling. Either put a secret up there or close it up.
Probably should just place a propeller block generator (or at least two sitting on the ground) there instead of an item block for two players.
The music is kinda short for the length of the stage.