Secret Domino Characters
To unlock Bruce as a playable character, beat the game with Mr. or Mrs. Domino. To unlock Pierre, you must achieve a score that the game considers "the best in the county" in all six stages. To unlock the alien domino, you must achieve a score that the game considers "the best in the U.S." in all six stages.
NOTE: Your rankings show up only after you have beaten a level, so you have to remember them. The rankings are from lowest to greatest as follows: Town, City, County, Country, U.S., World, Earth, Universe.