I made this game for the Ludum Dare contest #24, for which the theme was "evolution." In "Barnacles" you play a predator fish. You must eat the "barnacles" to survive. Each round, the game uses a genetic algorithm to repopulate the barnacles, and as a result they adapt to your playing style and evolve defenses. Usually, they eventually become well-adapted enough that you can't eat enough to survive and die.