Parallax

An odd mix of genres, Parallax has the player controlling a ship on a regular grid, in which the ship can only follow the gridlines (guided by joystick). There are glowing nodes throughout the grid, these are picked up when the ship passes over them, Pac-Man style. And there are four ships that circle the edge of the grid, releasing enemies inwards to the player ship. The player can fire as well, to destroy the enemies, but not the ships on the edge of the grid. A round is over when all the glowing nodes are picked up.