Happy to do so - this was my first experience playing CCR, and I was able to play a couple of single player and several multiplayer games.
First, I really enjoy the concept - the adrenaline rush of pinball with the drama of a cart race. It's a very neat marriage of the two.
The multiplayer is really quite seamless - each player presses start, the game will determine cart #, and you choose your racer/cart. At that point, the game proceeds as normal - you want to speed up by hitting as many flowing, looping shots as possible while avoiding drains, scoops and other obstacles that serve to slow you down.
You can earn items by completing the lane change sequence or hitting the captive ball behind the glowing chamber on the right of the playfield. The items I have seen are helpful to your racer, but do not hinder your opponents - I'm not sure if those types of items exist. Each player is racing towards the goal, as in the single player game, but instead of playing against 'bots', you are playing against the people beside you. This gives you the ability, as in couch competitive cart games, to taunt or congratulate your foes/friends, and I really enjoy that aspect.
Traditional multiplayer pinball games require you to utilize 'hotseat' to switch players. I'm not a huge fan of that, because you spend most of the time waiting to play.
This networked implementation solves the waiting game issue, and I'm thrilled I was able to sneak away for a while and blast some carts through space.
I wish I had more time to battle it out with @gstellenberg, @ryanclaytor, or three other random folks from the festival. It's wonderful.