Unlock The Memorial Option
Finish the game (by successfully completing the dog's solar system stage). This option includes a movie viewer and a music player.

Unlock Second Bonus Movie
To unlock the second bonus movie, complete the cousin collecting stage.

Unlock Staff Credits Stage
Finish the game, and then talk to the girl with the yellow shirt to play this stage again.

Unlock Comet Stage
Finish the game, and then talk to the astronaut to play this stage.

Unlock Cousin Collecting Stage
Find all the cousins, and then talk to the boy with the yellow shirt to play this stage.

Unlock Million Roses Stage
Complete the cousin-collecting stage, and then talk to the rose to play this stage.