just beat it... its pretty gd damn long for a launch title, prolly 20+ hours, i dunno i wasnt keeping track of time. the last lvl or 2 almost had me throwing the controller.... it gets HARD, but then again i unlocked new weapons for my 2nd run through and the first one i got so far is kick ass
plus theres stuff you unlock for meeting certain req's
oh and the 40 man online is fucking pure mayhem