May Day

May Day is a side-scrolling space shoot-em-up strongly based, and in fact legally infringing, on the arcade game Defender. You control a space-ship armed with a laser. Aliens appear scattered throughout the level, and may be seen on a radar screen positioned at the top of the screen. As is tradition, the aim is to destroy all of the aliens, and so advance to the next level.

While the graphics, sound and game-play are very similar to Defender, there are also a few differences. It is only possible to scroll through the landscape from left to right, but the ship can fire both forwards and backwards. In some levels, the ship's laser beam is angled diagonally downwards instead of horizontally. The aliens have their own movement patterns, and are not intent on kidnapping humans from the surface of the planet, as in Defender. While there are vector-graphics to indicate mountains in both games, in May Day, you can crash into this landscape. And finally, your ship is armed with a number of "Mayday" beacons which when activated cause the screen to flash and substantially slows down the movement of all enemies on the screen.

The game was only released briefly, before Williams' successful legal proceedings halted distribution.