By all accounts, Gameloft's recreation of the card game is done rather faithfully here. There are even multiple rule sets you can play with, in case the original game isn't enough. But, who could've guessed that playing against three AI opponents would get boring? Yes, you'll be able to adjust the difficulty of the AI from Easy to Hard, but that can't help un-break what's essentially a social game.
This could have been a great showcase of interoperability between the Xbox 360 console and Xbox Live on Windows Phone. It certainly couldn't take that much bandwidth, could it? Instead, UNO HD is primarily a solitary experience, and unlike other puzzle games on the platform, that just doesn't work. Yes, there is a pass-the-system mode, but considering how important shouting "Uno" is in the game, this feels like a poor alternative to just buying the damn cards.
See also: Windows Phone 7 launch games reviews hub
This review is based on a retail Samsung Focus provided by Microsoft and AT&T.