Not the most smooth and good looking interface i've ever seen, but an original idea nonetheless. It was really fun, and i can't wait for the maze tester. I think for the lava, you should have drawn some square, movieclip textures, and for walls maybe some bricks. If you want me to, you could give me the dimensions of the walls, lava etc. and I could PM you a flash file containing all the movie clips for walls, start, portal lava etc., so you just have to replace the current circles, with the movie clips I give you! I've got some awesome ideas for your game.
I gave it a five, so you don't give up hope of making more flash games.