Ye it's a really fun campain but you get quite annoyed when you die infront of the saferoom at expert level and it took you like forever to get there.
I think they should have devided the campain into three levels instead of two.
It would have caused less frustration if you died. I haven't finished it yet. I played it with a friend and I died as I said once next to the first saferoom and a second time during the final?. I didn't try again after that since it was just a too long walk.