Killer Bees (1985)

Killer Bees is an aim-and-shoot game, where the player faces swarm after swarm of... really, you can probably take an educated guess. Each wave of attack is composed of five buzzing enemies; to shoot them down, get them within your crosshair and fry your target with a pair of lasers. But don't let the title mislead you: the bees themselves are perfectly harmless. It's your energy that keeps draining away, and if you run out, it's game over.

At the end of a wave, you're scored by your remaining energy: shooting takes energy, too, so accuracy counts as much as speed. The next wave will drain your energy faster than the one before. You may pick a difficulty from 1 to 10, which determines the wave you start on.