One of the first things you'll notice when you pick up the controller, is that the controls have been subtly improved. The awkward weapon select wheel and the slight aiming stiffness of the first game have been replaced with a two-weapon system and a considerably more fluid aiming / moving mechanic. While it's still not on par with the tightness of Call of Duty 4's controls, they are much more comfortable now and definitely made running around the level easier.
The tighter controls definitely helps while playing online, because Resistance 2 has whole-heartedly embraced its arcadey roots. While the multiplayer in the first Resistance never attempted the gritty realism that CoD or Rainbow 6 revels in, Insomniac has decided to further push Resistance 2's multiplayer into Unreal Tournament territory. Not that this is a bad thing by any means, but it's a little disconcerting at first to see XP bonuses pop up all over the screen and watch as people activate their powerups (Berserks, as they're called) and start glowing or sparkling in front of you.
While these changes can be offsetting at first, you quickly realize how much they add to the game. The multiplayer in the first game was a little shallow and generic, and never felt truly satisfying (with apologies to the many active fans of it). Meanwhile, the gameplay in Resistance 2 is fast, frantic, and streamlined. The new squad based system and objective based gameplay mechanics means that even with 60 people playing, you feel focused and always know what to do. Feeling lost and want to know the quickest way to the action? Look for the objective marker on your map, and you'll be right in the thick of things in no time.
Unfortunately, in a surprising turn of events -- the graphics in Resistance 2 multiplayer are much of a mixed bag. The environments are much more detailed this time around, and way, way more colorful, and the guns and character models look quite a bit better -- but this has come at the cost of some serious aliasing issues. The whole thing looks gritty in all the wrong ways. It's surprising to play a game like Ratchet and Clank Future: Quest for Booty (also by Insomniac) and then come over and play Resistance 2 only to be assaulted by more jagged edges than the first Timesplitters game. It's hard to tell if this is something that will be worked out before the game launches in Novemeber, or it's a necessary compromise from having 60 players in the match, but right now it's a little disappointing.