Not... bad, I guess.
Good gameplay. Yet it was missing a lot of things, and had a lot of things that shouldn't have been there. Number one on the list were the graphics. All the terrorists looked like Jason in space or something. Plus, getting hit with an AR-15 isn't gonna leave a gapping hole one foot wide in a man's chest, let alone spray 40 gallons of blood on the walls. The weapon's grphics were great, but they looked kinda like the one in those Iraqi Army Operations game.
I'd suggest using the arrow keys on the keyboard to pick which direction you go instead of having to click the arrow on the screen.