Oooooh man was I pleased I didn't miss this. I wanted to post this review as this episode in particular does what a certain recent movie did not. It pays true homage to the game DOOM. Its plot is different yes, and the characters are obviously set in an entirely different universe (obviously the doctor who universe) however the feel, the pace, the references and the location are perfect. And for all original Doom fans listen out for the door opening and closing sound effect, it was the icing on the cake for me.
Please all doctor who and Doom fans alike, check this one out. its a gem!