I found one disappointing level in this game.  The airport level.  You have to kill hundreds of civilians.
Then you get offed.  I guess that's just like real modern warfare though.  Although I think you can do the level without firing a shot.  I'll have to go back and check that.

I never saw the skip option, just the choice not to fire a shot.

Well at least you don't have to shoot until the armed people come for you.

my favourtie missions on this are:

Cliffhanger
No russian
Endgame

cliffhanger is a perfect introduction to your new characters and to the stealth aspects of this game. it is also incredibly important as you need skills learnt in it in ENDGAME.

No Russian perfect for any blood thristy warmonger.

ENDGAME the greatest misson on any COD ever... when you got the knife in you and your yanking it out and the foutain of blood spurting up. the you flick it round and hurl it at sheperd and you can see his face, the look of pure terror as it spins dramaticlly towards him then *splat* whos for sehperds pie?

but nothing can rival the museum i would assume most have discoverd the red buttons and their purpose but if not, grab your self some good guns and where you start walk up to the desk...push the bit that says DO NOT PUSH SQAURE...and get ready... i got pretty far with just the m9 but got clubbed round the head at the last bit.