Seem to vaguely remember a Twilight Zone or similar along those lines. There's a planet that's trying to achieve peace. They're in the middle of a cold war, lo

Seem to vaguely remember a Twilight Zone or similar along those lines. There's a planet that's trying to achieve peace. They're in the middle of a cold war, looking rather like earth, half hour ends with the failure of talks and a nuclear war. Camera pulls back to two alien teens playing an intergalactic arcade game, now showing "game over". Perhaps the one playing the sim got bored and started star killing their own solar systems.