Here is the full list of all 12 UNO achievements worth 200 gamerscore. It takes around 4-5 hours to unlock all of the achievements on Xbox 360.
Successfully call UNO! and win the game.
Successfully bluff on a Wild Draw Four twice in the same game.
Complete a 4-player game of UNO®, in any mode, on Xbox Live.
Change the color of the discard pile 5 or more times in a single round.
Go out with a Wild or Wild Draw Four card.
Go out without ever drawing a card.
Successfully play 40 Wild or Wild Draw Four cards.
Play 40 Skip cards.
Play 40 Reverse cards.
Play 40 Draw Two cards.
Win 40 games of UNO®.
Win ten 4-player games of UNO®, in any mode, on Xbox Live.