Angry Birds : Space & Cut the Rope in the marketplace
Cut the Rope (WP 7.5 or higher) :http://www.windowsphone.com/en-gb/store/app/cut-the-rope/4c0cf9f4-31f0-444e-9321-0237d04f6a38
Angry Birds - Space (WP 8) : http://www.windowsphone.com/en-us/store/app/angry-birds/2e36df2b-44be-405d-873a-79fa190c9b35
This is what i was dreading. Don't care for the missing features in WP8 as a WP7 user, but app fragmentation is where it will hit. Hopefully this will be a rare case and for games mostly.