I had no idea this had just been released on Live. If you've never played it before, it's basically a sort of omni-directional bullet hell shooter with puzzle elements. I bet that's cleared it up. Previously this was on the N64, Dreamcast and DS - I completed the DC version a few years back and it was a simply amazing game. I'll post up my impressions later - could be much later as my download speeds seem to be around 56k at the moment.