Quirky and Fun
I love it! I don't know what it is, but something about actually being able to run around a map and do things is exciting. A lot of shooter games require standing in one place, and moving a cursor around the screen in hopes of shooting some fast moving object... but this is definitely a fun take on it, and is executed simply but well. Kudos to your use of 3d, I am sure it was a lot more work then it appears to be :).
-J