I saw this cool project (shoutout to @CL_Games) and thought I might be able to modify the game as well as the underlying mechanism. Bullets will fly towards one of the players randomly. If a player is hit, or they wander outside the play area, they will be eliminated. The top half will reproduce and the other half will be replaced by mutated variants of the top half.
Sometimes the players will only move vertically after several generations and I don't know the cause.