3D Platformer

You proposed modifications sound okay, be sure to make your new levels unique from each other and the tutorial. It is not clear what you mean by change the environment, if you are creating new environment pieces and models that should be good, but making new environments from the provided pieces is part of making a new level. Changing the player and enemy movement data is not clear that that would be significant, if you are making new enemy variety's that move differently that might be significant.