Solid hack. Very polished level design, although a bit too unforgiving. If you pay close attention you can usually figure out where to go next. Except for Maridia -- that was one point where I couldn't even figure out where to go with a map.
But overall, progression is great. Interesting mechanics are peppered throughout the game at a good pace. The difficulty is challenging but not exactly punishing, which is a great place to be. Fill that with some interesting sequences and departures from the vanilla game, and you have yourself a winner.