That would be great! Well, I liked the level layout. Little well-designed location with multiple sub-locations is good. Generally speaking I liked overall game design. I would suggest adding other worlds maybe a couple of the same size or a single bigger world with more opportunities to explore. Moving between these worlds would also be good addition.
Huh, that sounds like an amount of work. I think a faster and most significant improvement would be adding an alternative ending. Thus you can extend the story line. The game is good so motivate people to play it more =)