Roachez.
An insect simulator which allows you to test the durability of a colony of cockroaches. As you progress through the game, you get various unlockable weapons of choice. Starting with rolled-up newspapers and flyswatters, you kill as many of the colony as possible. But, with ongoing genetic manipulation due to pollution and cross-breeding, the roaches become tougher. Boots, shovels, insecticide and, eventually, thermo-nuclear weapons. If you can kill off all the colonies, you can enter the second phase of the simulation. Roaches as petz.