GermNation

Playing an epidemiologist at the Biological Control Institute, you're trying to control an outbreak of virulent germs in a controlled petri dish environment. This is done by colliding same-types of germs together, which immobilizes them, and then freshly exposing them to a third member of the same type. Timing is tricky, though, as individual germs will periodically retreat into a protective and unresponsive cocoon, emerging later -- sometimes changed into an entirely new germ type!

The ace up your sleeve is that you can dispense germs into the dish both horizontally, shooting them directly in, or vertically -- aiming them into L-shaped tubes atop the petri dish. Hesitate too long, and your dispenser fires the queued germ automatically, cluttering your game board and making it harder to find a cure! Once the dish is filled with enough germs to back up into the dispensers, the game is over.

(Fortunately, this should all be old hat to anyone who studied cellular biology at Video Game University under Dr. Mario.)