I really enjoyed the multiplayer side of the game and did it all legit, just played for a couple of hours most weeknights and then spend all weekend on it. I did have my rank reset a couple of times which pissed me off no end though. Also be aware that if the game freezes (which happened a lot) or if you leave a game/host leaves a game, you won't earn any experience. It's frustrating to be having a good game only for the host to disappear, as it kicks everyone out. Surgical Striker was probably the hardest multiplayer cheevo for me to get - I found it was easier to get kills on the hospital map on tdm, as there is a veil pool downstairs. Just lob one upstairs onto the balcony, hopefully planting it in a corner somewhere and wait for someone to run into it. Did not work all the time, but because the maps so small, I could probably get 10-12 kills like this per 30min game. Then just run to the veil pool to recharge, rinse and repeat.
The single player campaign wasn't as good as I was expecting - prefer the older Wolfensteins - but that does not mean its bad. Some bosses seemed too easy to kill, whereas others I found were just a complete pain in the arse (yes, I'm talking about you Hans Grosse!).