AWESOME GAME ! Great job !
I can't believe this is really your first flash game !
For a first game, i'd say you're godlike...
There was a lot of attention for detail (the guns move realistically, the sniper was awesome, i loved the way you could duck and take cover, that made this game so much better then the previous ones.
Sniper also improved greatly since last time.
In terms of gameplay, it couldn't have been done better.
One thing i'd like to see improved though: you should be able to buy new ammo with your cash/score.
I ran out of M4 ammo on level 2 (DE_aztec), and ran out of Deagle ammo on level 3 (DE_office). I was then killed because of my clumsiness with the magnum sniper rifle.
Anyway, just try to implement an ammo purchasing thingy, and it will be the bomb ! This is going straight into my faves list.
Keep on working on your scripting and i'm sure you'll get frontpage in no-time man ! You rock !