I gotta say, this is pretty damn impressive - Scratch is usually a 2D-only affair, so seeing something like this is a pretty strong demonstration of your prowess.
Main major complaints are the lengthy load times and the controls - I lack the Scratch expertise to help you with the load times (though I suspect using TurboWarp might help), but allowing me to use arrow keys to move and, say, Z/X to turn would've made controlling myself feel a lot less awkward.