Let's get this out of the way; Child Of Eden is fantastic. It's a brilliant game, breathtakingly beautiful and with an extraordinary design aesthetic. It deserves respect and recognition, and I hope that it achieves the success it deserves.
With that said, it's not quite as good as Rez. I like the music in this more (it's all by Genki Rockets so if you don't like them, you're out of luck), and the visuals are superior, but it's not as inventive as Rez and not as clever. But it's in the changing of one core mechanic that Child of Eden really falls down, and that's the multiplier system. In Rez, you gained points for every enemy locked onto and destroyed. For every subsequent enemy you locked onto before releasing the fire button, your multiplier increased by one, up to a maximum of x8. That meant that if you destroyed eight enemies (worth 100 each) individually you'd get 800 points, but if you chained them all together you'd get 800 points for EACH of them, for a total of 6400 points. This was a great system and introduced a lot of tension into the game–the balance between trying to destroy every enemy and getting as many big chains as possible was excellent.
In Child of Eden, this system has been dropped in favour of a combo multiplier. In order to increase this multiplier, not only do you have to chain together eight enemies before releasing fire, you have to release fire in time with the music's beat. While I appreciate the further integration of gameplay with music, this takes away from the strategy of the game and interrupts the ‘flow’ of things, if you want a high score you have to be constantly aware of the beat. In Rez, there were times when an almost zen-like state was achieved, a rhythm of action that was both satisfying and fun. That's not so much present in Child of Eden.
Another disappointment was the final level. The fifth ‘layer’ of Rez remains one of my favourite levels in any game ever. The fifth stage of Child of Eden amounts to little more than a boss rush, and although the ending is excellent, the lead-up is disappointing.
With all of that said, Child of Eden still delivers an amazing, emotive experience. It's a grand, majestic journey that's well worth taking. I'd love to see more games like this in the future.
Note: I don't have a Kinect, and so played this with the standard Xbox controller. It worked fine, and aside from a few gameplay changes, the ‘feel’ is very similar to Rez. To sum up, you definitely don't need a Kinect to enjoy this game.