Ok, just came back from watching this. AWESOME MOVIE! INSTANT CULT CLASSIC.
Ok, as you can tell from my username, I am a huge Snake Plissken fan. DOOMSDAY was pretty much a modified version of Escape from New York, but I was not pissed off at all. The movie really was a homage to the long gone 80's post-apocalyptic films. DOOMSDAY was in the spirit of the Escape movies with over-the-top action, humor, and for the new generation, over the top gore.
It's been a long time since I've seen the Mad Max films, but there is a chase scene that resembles the chase scenes in Mad Max.
Other than that, great fast-paced story, action, etc. Oh yeah, Rhona Mitra is smokin hot in the movie, in a heroic way.
Do not expect Mad Max or a Fallout movie when you go. Just prepare to be entertained!