As the title explains during the final boss fight after the second check point of the fight the game will hard freeze my system, spent 2 hrs on the phone with EA support/Specialist tried clearing cache, tryed unistalling game from hdd, even tried playing section on different xbox happens everything at about 45 seconds after the check point EA seems to think it might be a memory sector from the xbox and the game causing an error. My xbox is 250 slim with a 320gb hdd, other xbox tested on was 120gb elite, like I said both had same results

You are not the only one - http://secure.gamesas.com/forums/viewtopic.php?f=68&t=59449

The Alpha Ceph don't wanna be beat

I made it to beat the Alpha Ceph, ingamevideo start - freeze.
No chance to finish the Game.

Same problem with me as soon as i defeat the Alpha Ceph shows cut scene my box locks up and goes to black screen WTF crytek

For me, it helps now to start the Level new.
Finish the Game, but now it freez from time to time in the MP and have realy big Sond problems on my second playrought.