Shockwave

Shockwave is a modified conversion of Asteroids.

The player's ship is not rotating like in the original game, but can move in all eight directions. There is no flow in the movement, the ship is instantly stopping if the joystick is released. Running over a border enters the opposite site of the screen, which is also true for all the asteroids approaching and split under fire of the player's gun. Some of the destroyed asteroids leave small "M" icons, which represent minerals and should be collected. Minerals are the currency in the game world and can be exchanged for goods between the levels. The shop is entered after each level and is run by an unfriendly alien, but it is selling extensions to the laser weapon (e.g. longer or faster shots), a shield, or extra lives. On later levels additional foes like rockets, shooting satellite stations or huge alien spaceships are coming for the player.