At the top of the screen, the #/# is the number of petpets you've gotten in bins/the number of total petpets in that level. The number in is the number of petpets that have already been released in the level.

Pay careful attention to the number of petpets you need at the beginning of the level because it does not say anywhere after that, but if at any point in the level you 'pass the point of no return' or drop too many petpets, the level will end.

Always collect the stars, as they will earn you more points.

If you can get the petpet exactly in the bin, you will get double the points for that petpet.

You can drop the petpet into the bin beyond the walls of the screen.

You cannot drop a petpet into a bin that already holds a petpet.

With the orange beams, you can hold down the arrow keys to keep the beam flat until you drop the petpet into the bin. This takes a little bit of practice to get right. (This is especially helpful in levels 4 and 5)

The beams with the red dot will catapult the petpet into the air if you land on it for a few seconds. The petpets rarely end up in a bin if this happens, but the beam will disappear after its been 'popped'.