This is very cool, very big, and wow you consider it still unfinished apparently? I mean okay, its visible by the varying quality of levels, but still its amazing. I really like that by combination of colors and music you created multiple moods in the game. The landscape in the background was also very nice. And the main character with its wacky animations, cool. Some story is there so also great.
Point number one: please attach source to used assets (music, sound especially). Unless if its in public domain or you got the license, but its worth to give credit! Even if its just website.
I think I found a bug: I could use healing without mana.
I defeated the captain boss, but now i don't really know what to do next. The previous area is really dark, and can' t seem to be able to jump up that steep wall. Any suggestions?
Beyond that I don't know what to suggest as you are probably well aware of missing parts/mistakes. Its just a very well made game. Wonder how it would look like if it was completed.