This game was released (demo at least) in 1981 by SierraVision on 5.25" floppy boot disk for the PCjr. Here is the add blurb from the box:
They have landed and are taking over the city. Steadily they make their way across town, destroying everything in their paths. The town has been evacuated, and your regiment has retreated, leaving you alone in the city at the mercy of the aliens.
The aliens have you aurrounded, and laser shots fly from all directions. Your movements are confined but you haven't given up. If you are to live, you'll have to concentrate on where the shots are coming from and where you're going because if you don't you'll get caught in the CROSS FIRE. Add
Did You Know?
The keyboard controls allow you to fire in all four directions, while the joystick lets you fire in the direction you're traveling. This means that the keyboard controls are actually more effective for playing the game than the joystick.
The Composite-mode colors of the PC version are identical to the Apple version.
Both a PC and a PCjr bootable cartridge version of this game exist. The PCjr cartridge version is differently colored.
There is a Windows remake of the game, created for the Retro Remakes competition 2006, with the title Gridfire.