That looks really nice. Colorfull graphics. Me likes!

A few tips:

Some people may find the bouncing noise annoying after playing for a long time. Maybe you can change it to make it less obvious, or play different sounds for more variation. Also, when you are inside a building, it would be nice to have thick walls. Now they are just simple poly's. You might also want to replace your explosion particles with more transparent ones. You can now clearly distinguish the different particles.

I noticed every object has a shadow. What kind of technique do you use for shadowing?

Keep it up. Would love to see more!