Continuing the epic story, ME2 just doesnt hold its own against the original.
Sadly it doesn't. Sure Bioware removed some of the awful aspects of the first game: the Mako, and the empty worlds where you used the Mako, the cluttered weapons/armour menus. But what did they replace that with? Linear maps, armour and weapons that practically don't change throughout the entire game, and a new power system that stops players from dishing out their amazing biotic and tech as much as they want.
Now I'm not saying ME2 was a bad game, far from it, its a really enjoyable game. But some of the most noticeable changes Bioware made sucked. Thankfully others weren't so bad: the combat is now as solid as a shooters, characters are so much more fleshed out, the graphics are far better, and the game manages to hold to its grim atmosphere consistently.
All in all, Mass Effect 2 isn't what I'd expected or hoped for but it is still an beautiful, incredibly fun game with a story that is beyond superb.