Oh, yeah. Zoo Keeper is great. There's also a newer version of the game here, which has a Quest mode where you have specific targets you have to meet. It's all in Japanese, so here's a translation of what you have to do:

1. Catch 20 lions, leaving the other animals.
2. Catch 15 more giraffes than pandas, or 15 more pandas than giraffes.
3. Catch 30 groups of animals by cause and effect. (Eliminate rows or columns underneath to cause a chain reaction, a process which boosts your points in normal mode. You can keep matching groups as the reactions take place.)
4. Catch only one group of each animal. If you repeat any one, you have to start your selection over.
5. The slot machine: Click the flashing box to win a prize.
6. Now, don't click the flashing box. (Usually, if you do, it will clear all the animals of the chosen type.) Instead, get it to fall to the bottom of the screen.
7. Catch seven groups of animals without causing a chain reaction.
8. Catch five groups of four or more animals.
9. Catch ten groups in columns, not in rows.
10. Score as many points as quickly as possible to fill the timer.

_{List and link stolen from jay is games.}