Mass Effect 2, while being quite clearly a sequel to Mass Effect 1, is a combat-heavy, and dialogue-heavy Third-Person-Role-Playing-Shooter. That's a mouthful.
In contrast to Mass Effect 1, which is purely story-centered, Mass Effect 2 is a departure from that, seeing how the combat is actually... Almost fun. I say that: "ME1 is 100% Story, and ME2 is 50% Story / 50% Combat."