I played through about halfway through my review copy last night. It definitely has a charm to it and the combat is decent enough. There's a bit more variety than I was expecting, but I'm at the point where it's starting to drag for me. A 5 is definitely underselling the experience, especially for IGN's 7 (or is it 8 now?) to 10 scoring range.
The platforming stuff is pretty decent, though it's more like an extension of walking than anything else. I've spent more time picking up collectibles than anything else, which has a weird allure for me. I've enjoyed exploring the areas collecting everything in sight.
The graphics are definitely getting a bad shake from IGN too, but they're decent enough. Really, they're just uneven - some parts look great, others terrible. The particle effects in particular look pretty poor, and there's some slowdown when a bunch of guys are on the screen, so that's the worst of it.
Overall, it's just a mindless game. It has a certain charm to it, but there's been nothing special about the experience thus far. IGN is right about one thing - the game is short. Like I said, I'm about halfway and I've probably played for around 3 hours. I believe there are some extra modes outside of the story, plus extra difficulty levels that alter your life bar (no more auto-recharge) and such, but I still need to check back in on that stuff because my memory is a bit fuzzy.
As for the topic at hand, waiting on a price drop wouldn't be the worst idea in the world, especially if you have a backlog.