Cool way of implementing the limitation!
Exploring the castle was a bit hard at times, though - there wasn't a clear route or objective so, unless I already knew the position of an obstacle or key, I'd have to just wander around the castle - maybe some landmarks in the castle would help navigate it?
I would also definitely note the controls of the game down somewhere. It took me a long time to figure out that I needed to use Z, X, and C for other movement shenanigans.
When I got the hang of the controls, though, they were quite fun. Loved dashing around like a maniac on the ground!