Terrible. If you were, like me, excited to relive the amazing game play and feeling of the old games, DO NOT BUY THIS. The controls are way off, there's no way to suspend your game play in challenge mode with the old levels, and you can't play multi player at all! Only multi player games are the party games and they ruined the mechanics of those as well. Totally useless to me when all I wanted was to play the old Monkey Ball levels and share the awesomeness and competitiveness of the old games with my fiancé.
Why even add them in if you can't save your progress? 60 expert levels in one sitting? Come on. And you can't even select individual levels from the old games, and retry takes you back to the beginning of the entire challenge, not the course. I am completely disappointed.
If you are new to Monkey Ball, this will likely be fun for you, but definitely not when you are a seasoned Monkey Ball player looking for the feel of the old games.