If you like Mario or Sonic or even the Olympics, you're bound to like this game. I recently bought Sonic and Mario and the Olympic Winter games for the Nintendo DS. There is also a Wii version and I really enjoy playing it. There is an original version which is Sonic and Mario at the Olympic Games. There are a few changes I'd like to talk about that are different in the winter version.
New Characters: Four new characters were added to this version. From the Sonic side we have Metel Sonic and Silver -- both very cool additions although I'd love them to add Tikal to the game. From the Mario side we have Bowser Jr. and Donkey Kong. My sister loves the addition of Bowser Jr., but I would've liked to see more girls, for example, Toadette and Birdo, because overall there are far more male characters than females.
Adventure Tours: This is a new addition that I am very pleased with. In this part of the game you get to team up starting with Mario and Sonic, then you add more and more people to your team as you work your way up the game. The story goes as Bowser and Dr.Eggman have stolen all the snow spirits and now it can't snow anymore. You must beat challenges to get more crystals which help you advance to save snow spirits. If you beat challenges held by other characters they will be added to your team. This feature gives the game more purpose and more to do.
Winter Events: Obviously winter events make up the game, they range from skiing, to sledding, to skating, to my personal favorite, ice hockey. I found these events harder to learn but a lot more fun to play.
Overall this is a great game and I recommend it to anyone who likes Mario or Sonic.
Have fun gaming,