In short, over 90 years of firearms at the players disposal (however, you can’t use future weapons in the past. You can use a Lee Enfield No.I Mk.III in Vietnam era, but you can’t use an M249 in WWI), all with accurate models, sounds, and most importantly ballistics. “What if?” scenarios (example used is a Navy SEAL platoon vs. WWI Czech Infantry, and you can even change their armament, i.e. the SEALs get 1911’s and the rifle platoon gets RPG 7’s). And of course, multi-player containing all of this plus the ability to do co-op with friends.
It’s supposed to be released by late 2007, but I think it’ll be worth the wait.