Play as D/M*?0:
Successfully complete the game with a "best in the US" score in all six levels.

Play as Bruce:
Successfully complete the game as Mr. Domino or Miss Domino.

Play as Pierre:
Successfully complete the game with a "best in the county" score in all six levels.

Grandpa's In The House: Otaku Grampa:
Press all the trick buttons at once with a chain, to see Grandpa go psycho, with his muscles bulging out and him screaming as if he were a Japanese character from an Anime or Otaku film.

Grandpa's In The House: Girl in black:
Press all the trick buttons at once with a chain to see the daughter in black rather than white.

Phat Tony's Casino: Stopping Mr. or Miss Domino:
Mr. Domino or Miss Domino, depending on who you are playing, will be moving back and forth in a line trying to stop you. If you put a Domino piece in their way, they will stop moving and just sit there.

Being one with the dominoes:
To get all the dominoes to go down, and at the same time fall down with them, you must go throughout the level putting a non-stop domino trail until you get back to the start. Push the first domino that you set down to start the trail, and they will all go down and end at you, knocking you down with them.