Sweet game!
Looking very good. Great music. Great 3d graphics. Well done!!
The tank's cool.

Ideas/critique: 1) I think it changes to "night" too fast. Just slow that transition down maybe?
2) Anything that explodes... put some depris in there or something. Just don't let it disappear the way you do right now? The wall, the planes, the tank... they all get damaged and then they just disappear. It would look even better if there was something left over afterwards... whether it's a wreck or just pieces lying around...

Keep it up! Very well done!