For the past few days, in anticipation of the release of this final chapter (in oh say... about three and a half hours) I've been playing the demo, while I played through the story demo in my two favorite classes (Infiltrator and Vanguard) I spent a good chunk of my time playing the Co-op multiplayer mode (once again mostly Infiltrator and Vanguard).
While I can't really give an accurate review of what the final game will be like, the demo was a blast to shoot through. The most obvious difference between 2 and 3 that stands out on first hands on was the controls. Shep moves much more fluid, especially when using the storm dash to rush towards or away from opposition, the control is much tighter and controlling Shepard while storming feels like I can actually control my character rather than the clunky feel of the previous games. The cover system received a pretty fantastic upgrade, Shepard can now jump between covers, move around corners, overall actually get the drop on enemies rather than the more tired "hide behind box, peek, shoot, hide behind box" gameplay of the previous titles.
Combat is improved greatly, new powers and also some powers that don't force you to go into cool down mode. For example, I never liked how switching ammo types was a sort of "power" for characters who had different ammo types. You are not forced into that awkward cool down period when you switch ammo types. Melee combat is greatly improved, rather than just an elbow to the face sort of melee attack, laying the smackdown on some Cerberus ass has gotten much more stylish this time around. Melee attacks can be combo'd and also you can do a heavy melee attack that can seriously knock back whoever has the dumb luck to be on the opposite end of Shep's back hand.
All these amazing improvements play well into the co-op multiplayer. Co-op is pretty much a hoard mode (within the context of the demo) but each wave isn't just another sweeping stream of baddies asking for a tungsten round 'tween the eyes. Different (random perhaps?) objectives are thrown in, from hacking terminals to taking down specific officers make for a far from cookie cutter hoard mode. It's fun and seems much better than I anticipated, I admit I was one of those "Noooooooooooooooo EA you *bleepbleepblerpitybleeps* Mass Effect doesn't need multiplayer" types of gamer when they first announced a multiplayer aspect to ME3.
With that said... as I finish writing this review... we are looking at just about 3 hours left... 3 more hours till I pick up my copy of ME3, 3 more hours till I get to stand in Shep's boots once again.