To keep up with Dory, grab all the bubble rings.
Avoiding Bruce
On the level 7 (the Submarine), if you see an ''!'' over Dory's head, it indicates you should move or Bruce will catch you. To keep away from Bruce keep rotating the Analog-stick.
FMV sequences
When you complete a level or are at the middle of a level, you will see an FMV sequence from the movie Finding Nemo.