DOD Source. I gave this whirl late last night since I bought it like over a year ago with my HalfLife 2 purchase (it came with it) and was finally released this last weekend. She crashed on me twice, I think because my sound card drivers are fubared. Regardless, it looks a ton better than the original, obviously since it uses the Source engine. They lessened the power of the BAR (Browing Automatic Rifle) and increassed the kick of it, so you really have to utilize burst shots or within milliseconds of aiming straight, the kick throws your aim to the sky. I haven’t tried any of the other kits yet because I only got to play for about 10 minutes, but overall it’s still got the WWII charm of the first, focusing on intense urban combat vs. all out war like Battlefield 2 does.