Early costumes
So it seems as if the costumes in the game were originally going to have completely different designs, inspired by Rayman 4:

This bigfoot one turned into the "Gangster" costume:
This bubblegum one turned into the "Punk" costume:
This one with just glasses turned into the "Grandmother" costume:
This one turned into the "Rocker" costume:
This one turned into the "Funky" costume:
So it seems the costume designs changed later in development to match what they were using for the final console versions, while their functionality remained the same as originally intended. This is probably why it's a bit odd how the grandmother costume is used for distraction/stealth now, since it was originally going to be the invisible costume etc.
Enemies
A Rabbid enemy:
Funny enough this one is actually placed outside of the level Infernal Escape: Some enemy from the Sweets world:
Some skull with wings:
Small lividstone:
Unused levels
There are 3 unused levels in the game, which can be accessed through a glitch in the game. Basically in the game the Mode7 levels (the 3D ones) are separate from the normal levels, but the normal levels are still indexed as if the Mode7 ones were there. Because of that there are 3 normal levels which never get used, but apparently still exist. They all appear exactly the same, but using different tilesets depending on the world (which all look completely wrong...). Now these could very well be leftovers from other games by the same developers (there are a ton of those in here...), but it could also be some test stage they use to test object.








