It's not a bad game, but there are things that prevent it from being a great game:
-It starts good, but the level design gets hiccups later on
-Later on the levels have questionable checkpoint placement
-Motion controls on some of the Color power ups was wonky (was fixed in a recent patch)
-100 rings = No Lives, 1ups are rare, so after 20 rings collecting more is pointless (this was fixed in a recent patch)
Overall its a good game, but again not great.