Posted on 12 February 13 at 21:37, Edited on 12 February 13 at 21:41 by Das Kuhnen
These gems are completely separate from the main games and not included in the Ultimate Collection. They are usually pre-existing Kinect Sport mini games, but have their own leveling system and achievement lists that differ greatly from their retail game counterparts. So no, they do not "stack" in any way, as it's not possible.
Can't wait for bowling! Managed to hit a 300 in Kinect Sports 1.
Turns out, actually playing a game you want to finish helps you complete it...