The object of the game is the same as that of Cricket - to close all the numbers before your opponent and have an equal of greater point total than him.
The score board is set up in a similar fashion as in Cricket with the following exceptions: The B (for Bullseye) is placed first above the 20 and after the 15, the numbers are extended down to the 10.
The major difference between Mickey Mouse and Cricket is that once both players have closed a number, further darts thrown into that number's scoring are gives the point total of that dart to his opponent. For example, if my opponent and I both have the 20 closed (ie; we have each scored 3 hits on it) and I score another 20, my opponent now gets 20 points.
The strategy in Mickey Mouse is pretty much the same as Cricket. However, the reason the "B" is placed above the 20 is that it is wiser to close the Bullseye first lest attempts at closing it later in the game result in giving points away to your opponent.