From the Boardgame Geek:
Shoo, get away! Was that really Gary Gouda, the mouse, cheese-hunting again? The greedy mouse just can't stop! Not one piece of cheese is safe, and he risks becoming stuck in the mouse holes with his big belly. He really should have memorized by now which holes he can pass through after eating one, two, or more pieces of cheese! He also has to avoid the quick pet cat, Kiki, who always seems to be ready to pounce on the next mouse hole. Who can help Gary memorize the best way to the target mouse hole and collect the most pieces of cheese?
The bottom of the Gary Gouda box contains the game board, which resembles an apartment with 16 rooms arranged in a square and archways connecting each pair of rooms. Before the game begins, players slide archway tiles into the walls to adjust the heights of the various archways at random. The cat token is placed in front of any orange mouse hole to keep his eyes out for Gary.
On a turn, a player wants to move Gary from a corner of the house, pick up at least one pieces of cheese, and make it safely to the target corner without being seen by Kiki. To set up a player's turn, he draws four cheese slices, then places them in the rooms designated on the slices; he rolls the color die to determine where Gary starts and where he must move to. He is then free to move Gary through any archways possible – as long as he doesn't enter Kiki's sight – to reach one or more pieces of cheese. Gary eats this cheese immediately, with the player stacking Gary on the cheese slice to make the mouse fatter. If Gary ever gets stuck trying to fit through an archway, then the player's turn ends and any cheese on Gary is removed from the game; if a player reaches the corner, he claims any cheese eaten.
The game ends when a player can't place out four slices of cheese. Whoever has collected the most cheese wins!
Language Note: This is an English language edition game.