We went in expecting not much: it's a movie based on a videogame -- how good can it be? We just went to see stuff being blown up, and we weren't dissapointed. I don't have anything to add to halfnorn's review of it -- except that I could have done without the final wire-fu sequence. There is no wire-fu in Doom, only automatic rifle fire!
Also, Dr. Carmack? Named after John Carmack, who created the Doom engine.