The p90 pisses me off. It's better than the AK, it's better than the M16, it's better than the M4. Quite frankly, at any distance shorter than sniping distance, the p90 is the gun to have. I hate when *one* gun is more powerful.
Oh well.
Just 1000 pt'd it yesterday, too. Try playing "One Shot, One Kill" or "Mile High Club" on Veteran. Talk about fucking hard? That's fucking hard. There was a section in the second-to-last level that was quite difficult on Veteran, also. Flashbang heaven.
Most challenging single-player I've ever played, because the AI is actually quite intelligent. You move more than a couple feet one way or the other, and they'll respond differently. As such, every time you die, it's a different person or a different angle.