Really nice
It is good to pass the time, but There are some minor bugs, like the Stair only gond downstairs, wich everybody mentioned, and the death counter at the end did not work (it showed function() - something, and I died twice). The "bosses" were all pretty easy, too. Maybe a more improved battle system will make it possible to have more difficult battles without just raising the power of the enemies.
Anyway, it runs smoothly, the dungeons are all very well designed and the "simple" graphics are very beautiful.
I just didn't get what that red bar that filled up when you get crystals was meant for.