There's also Kinectimals, and they own the Max and the Magic Marker team (although the iPhone version of that particular game has external publishers).
Saw this last night/early morning (about 4am), and thought I was seeing things.
They've obviously realised that the target audience who would buy a Windows phone for Xbox achievements is probably 0.0001% of the audience who would buy an "Xbox" game on their iOS, with in-app purchases.
Downloaded it today, but for whatever reason, it won't log into my XBL. I hit sign in, and it sits there, and then just stops. Not sure what's up with that.
For anyone having trouble with the Sweet sixteen, Autobiographical or Better than half achievements use this cheat sheet. You might lose like 15 seconds tops typing in the letters on a laptop.