Saw it yesterday, and it was about what one would expect from a piecemeal arrangement of "24"/Panic Room/Die Hard.  And although ther were major plot holes and loose ends, I didn't hate it, and was not bored.
Spoiler: 
I really thought that they were going to be some go the "plot twist" route, and either say that Mars was somehow "in on it", instead of just a raving psycho, and/or that the "masked gunman" was going to be someone from the first scene.  But they played it completely strait which is unusual these days.  Oh and I also found it interesting/refreshing that none of the bad guys had to be killed more than once  
Overall I'd say 6.5 out of 10