Unlock Online Levels
When the message "Not Qualified" appears press F3 to unlock that level

Third Person Mode
Press the ~ key to bring up the console and enter a code below
behindview 1 - 3rd person view

Weapon codes:
Use one of the following entries with the mpcheat changeclass code.
ak: AK47
ak74su: AK74SU
ar: SAW
f: Fists
g: M16A2 with grenade launcher
gp: AK47 with grenade launcher
m4a1: M4A1
r: Grenades
rpk: OpFor machine gun
s: M81 sniper
s24: M24 sniper
svd: Dragonov sniper rifle

Unlock any online level:
Press [F3] when the ''Not qualified'' message appears to unlock that online level.

Sniper view with a regular gun:
Note: You must be in a server that is running in cheat mode to do this trick. Type mpcheat changeclass s at the console window, thengo to the scope on the sniper riffle you just created. While in the scope, type mpcheat changeclass g at the console window. Note: instead of g (grenade launcher), you can use any gun. You will change to the gun you selected and will still have the scope on.