Great idea.
This is a great idea... keep up the work.
Might consider putting in more characters and things to interact with. Also try and make it so you turn around corners instead of always facing north (i know that would take many more drawings, but it would make it easier to move around).
I got a whole bunch of ideas for you, but i won't drag it out. If you want to hear them email me.
canadianchico@hotmail.com