Huge agree on your point about Stage 4, that and a few other points interestingly come across as a fair bit better designed in its Retro counterpart. It's made precarious to maintain your berserk levels when the stage itself seems to be ostensibly running away from you.

Incredibly refreshing to finally see not only some praise of this game, but also that you raise my favourite element of it - that its puzzles all take place in one (mentally) rewarding 3D space. A puzzle game with a level select, as this could so easily have done, would have fizzled my interest out because it turns an explorative experience about discovering the rules on your own terms into a task checklist that could quickly feel insurmountable.