Online is what gamers have demanded because there really wasn't anything else missing from Guitar Hero. It's good to finally have it, but it's always more fun to party in person than via satellite. Battle mode, the new multiplayer option, trades out star power riffs for weapons that hinder your opponent: you must whammy every note, or one button is "stuck."
Co-op has a big advancement, and takes a tiny step back. You can now do a co-op career mode, which is surprisingly different from single-player - with an alternate path of venues and a shuffled playlist. Oddly removed is the stat-tracking for each guitarist; it's now replaced with blanket stats. Note: Co-op quickplay was in our review build, but we're told will require an automatic (free) download update via Xbox Live.
Guitar Hero II on 360 featured a minor graphical touch-up. This game, however, looks truly next-gen. The character are immensely detailed, brilliantly animated, and actually synch up with the songs. The same goes for the rest of your band. The HUD has been streamlined, and makes it easier to denote both when you have star power and how big of a combo streak you're rocking.