In MW2, online and offline play do not cross over. You either complete challenges and gain levels in one or the other (at one time). Hence, you cannot unlock online weapons by playing offline.
Reach level 70 and it magically appears in your list of weapons.
man ... in cod4, infinity ward didn't focus on offline multiplayer so you cant level up but in cod mw2 this problem is over ... GHOST out . (overlord mw2) EDIT BY SOMEONE ELSE: The only way you can is to hack or mod, I dont know how so get black ops when its out or get MW2
Go up levels
well if u wanna do it online go to multiplayer and click play online then click find game then click Team Deathmatch Same goes with offline go into multiplayer but then click split screen
use the attachment akimbo
You cant.
mw2
Sleight of Hand Pro
If you're referring to skirmish mode, you have to play online and unlock the classes there, for it to be available in offline.
Yes you lose everything but titles and emblems
10th lobby
No