A beautiful game with PHENOMENAL online capabilities.
However, the Online is a whole new beast. BEYOND WORDS. I played for a good 7-8 hours lastnight online, and not ONCE did I experience a frame skip, or any lag whatsoever. My only bone to pick with Resistance online is the voice coms. Sometimes people start cutting out and their voice com starts lagging really bad. And after a game or two, you're lucky if your mic works at all. However, I have a USB Mic, and I found when you unplug/replug the headset it, it usually fixes it, so its not that big of deal, but a minor inconvenience.
While I admit there are a few semingly cut-corners in the single player game, and the levels aren't very long, It is still a great game. Also, This game is no cakewalk. I started the game on Easy mode, and I die a good handful of times every level. This could be because I am not very good at the game (most likely) but I'm pretty sure the 7-8 (or more) chimera on the screen at the same time contribute to the cause. It is by no means an easy breeze-through game. It implies strategy, flanking, and encourages usage of all your weapons, and grenades. A good plus is there are usually plenty of health pick-ups scattered through the levels (at least on easy mode).
All in all, the free, lagless online is what makes this game the phenomenal hit that it is. The encouraging of grouping up and communication, the strategies involved in the game modes, and the level layouts, packed with rubble, debris, and other items to take cover behind. Not to mention the insane amount of level customization, and the amount of awards/medals you can get which raise your "rank" (even in unranked games), and unlock more outfits/accessories to better differentiate your character from the rest. All this togeher makes for a lasting online gamplay, and almost infinite replayability.