Well, in my opinion the first is the worst, still a good game but still, it is worth playing i think because of the story. Mass Effect 2 is where it gets all good, story wise and game-play. But if you like SciFi and RPG/Shooters and a good story, Mass Effect is defiantly one you should check out. However if you play Mass Effect 1 and don't like it, you can just move straight on to 2, apparently it does make sense you just don't get to import your save games unless you complete the first.