This is how a classic card game comes to life in modern era.
Graphics are colorful HD quality and they are just beautiful to look at. If you like the look of Mario games you'll definitely enjoy the style of UNO. There are not so many sound effects, but they all work well and in this kind of slow paced card game you don't really need many sound effects. Music flows steadily in the background giving the experience a relaxing sensation and it does not irritate you in any way.
Gameplay is very simple consisting of the use of a few buttons and if you have ever played UNO and video games then the learning curve is pretty much nonexistent. There are a handful of different decks and game modes to choose from and they will satisfy your need for variety in terms of visual style and game modes.
Online is really what UNO is made for, since the single player mode will not keep you interested for long. You play with 4 other people in and a very nice feature is that if 1 or 2 players leave in the middle of a session the AI will continue from there seamlessly. This keeps the game going and prevents irritating stops and reloads. You can also add your Xbox Live Vision camera right beside your card deck and it is fun to see who you are up against. Voice chat is here as well, but I prefer to keep it off, since 2 random people usually have very little to say to each other.
Bad thing is that in the multiplayer you can't create a distinctive party to play with specific friends like you can in Halo 3 or Call of Duty 4 for example. One player needs to create a game and then others can join it from a separate game searching menu.
I'm very pleasantly surprised with UNO and it is at its best in short sessions every now and then: this is a perfect way to relax between hectic shooters or heavy strategic challenges.