Sweatshop is a game dramatizing the plight of Third World sweatshop workers, created by Littleloud for
the BBC's Channel 4, in the form of a tower defense game.
That is, the creeps are items being manufactured and move along a conveyor; the towers are sweatshop laborers, who "add work" to each item until it is complete, and if too many incomplete items get to the end of the belt, you lose the level, and are berated by your obnoxious boss.
You can, of course, increase the speed of the belt to make your workers work faster, and in later levels, you must also do things like place water coolers strategically so they don't keel over from dehydration. Workers can become badly injured on the line, and even die.