This level is insane towards the end. The Russians randomly fire. You never know when it's safe to shoot back. It's a crap shoot at times, yet logicaly set out for you. I spent probably 4-5 hours trying to beat the level last night. For some reason, I didn't even get mad or curse my television. I have to give props to Treyarch for such a challenge.
If you only play multiplayer and think campaign is boring, Try mission #4 on veteran. It's fun and challenging. I'm not throwing in spoilers. I made it to the last checkpoint before I read anything on the net about the level. I didn't need any info, I was doing it right, just need some luck...or skill, lol. Cheers.