Here's how we reviewed Sonic CD last year (72%):
By virtue of being a port of a title from 1993, which is relatively early in Sonic's legacy, the elements that have become the clichés of the series (rings, end of level bonuses, springs, etc) are all on show here in their classic format. If you've ever picked up a Sonic game, the tropes are all here. In that sense this is a fitting title.
It also means that there's no real variation on your goals in the game. You start at the left hand edge of a world, and you need to guide Sonic to the exit somewhere on the right hand side. There are multiple routes through the various platforms, cliffs and caves. Your goal, through multiple replays of each level, is to find the route that lets you collect as many spinning rings as possible without dying through impact with spikes or roaming creatures of unusual size (although unusual size, when you are a speedy hedgehog, is a bit of a misnomer).
Sonic CD is an accurate port that's missing the correct hardware to play it properly. It's a curio for the hardcore fan while they wait for the next actual Sonic adventure on Windows Phone, but one I think they will appreciate. For the new player to the game, it's very nice looking, and I'm sure you could blunder through it quite happily, but you can't play accurately. And accuracy is everything for Sonic the Hedgehog.
Here's how the Windows Phone blog describes the weekly deals:
Each week the Store’s Red Strip Deals Collection will feature three popular apps and games—typically one Xbox game, one indie game, and one top-rated app—for at least 50% off the original price. (In case you’re wondering, the collection name derives from the red stripe you’ll see around each discounted app’s icon in the phone Store).
The Red Stripe Deals can be accessed via the Windows Phone Store collections feature, either via the desktop website, or via the Store app on any Windows Phone device.