Haha, I went to face Lewis Legend again with the intent of getting his achievement, but only had to do his QTE once before I got it. So yeah, it's cumulative..
Big Bacon, IGN IS the site that gave ME3 a great score. In general, just don't trust big sites. That said, Lollipop Chainsaw is a great, albeit short game. However, the differences between difficulty, many unlockables and just the characters in general make it a pretty nice game - just maybe not worth 45-60 dollars. Probably closer to 30.