Child of Eden
This was actually the first time I actually played through this game to it's completion instead of just dicking around with replaying the first level... I forgot it's suppose to be the spiritual prequel to Rez, story-wise, but the gameplay felt more like the spiritual sequel nonetheless... Sure, I beat it in under 2 hours (with only having to replay one of the previous levels before the last one not only to unlock the l, but also to just 100% said replayed level), but the overall experience was more than worth it and actually made me want to replay Rez again... too bad I don't have a Dreamcast copy, a PS2 copy, or an 360 of my own to actually play it, anyway...
(And to think I was going to cheat a bit by saying Rayman Legends Origins, on the ground of this time replaying this game alongside my mother in [local] co-op... considering I've only beaten the game solo up til then...)