Incredible
That was an awesome game!!!
Things I loved:
1) EVERYTHING could be blown up!!!
2) FLOATING BODIES :D:D
3) Simple graphics
And now, the suggestions:
1) More weapons, more fun :D. It'd be really cool if you could pick up the weapons of the guys you kill.
2) In the first level, I know you accommodated for 2 grenades for each orb, but maybe if (taking my first suggestion into account) you have a tool that breaks walls without wasting grenades, because I threw a grenade at one of the bad guys, and I couldnt finish the level. Either that, or more grenades... or the ablility to pick up more grenades; you don't want to start with too many...
3) I dunno about the whole orb thing. Maybe if you had to blast your way into offices to steal top secret documents or something (hate to sound cliche, but thats the first thing that came to mind), that would also be cool. But this is only a suggestion. If there's a back-story to the orbs then leave it. I can just see HUGE potential from what you given us here.
Final Thought:
In your game, the best aspect would have to be that the environment is able to be completely destroyed. With this knowledge, you could possibly have hidden weapons you can only access by blasting your way to them or something. Like I said, there is huge potential here for your game. Very good work.