Some neat levels here! 'More Doors' is particularly fiendish.
If possible, it would be nice to be able to hold down keys to keep moving in that direction and, more importantly, to undo long chains on moves without having to tap the Z button repeatedly. At the moment, the movement feels a tiny bit sluggish and I found myself accidentally nudging things in the wrong direction a few times as a result.
(I don't know if you're familiar with the Puzzlescript engine, but it's designed to make building grid-based puzzle games very rapid, and can be a very useful for prototyping / experimenting with mechanics.)
Look forward to seeing how this develops :)