When On-Line began producing games for the Atari computers as well as the good old Apple II, it was a major piece of good news for owners of the 400 and 800. The Coarsegold, CA company has done it again by releasing this home version of the popular Astro Blaster from SEGA / Gremlin.

When On-Line publishes a game, prospective purchasers can generally count on fast action, superb graphics and stirring sound effects. Threshold easily keeps the company's sterling reputation intact.

The game opens with five ships docked on the right-hand side of the screen. The top ship explodes off the pile and heads into space to do battle.

The player controls the ship, using the joystick, moving side to side at the bottom of the screen. The player must destroy an incredible number of screens of aliens to win this game.

The player can enter warp drive by pulling back on the joystick. This slows all action on the screen down to a crawl. It is then possible to shoot the enemy and actually clear a screen. Only one warp drive per ship is allowed.

The enemies are constantly dodging and weaving while they blast away at the player. Clever strategy plays a very important role in this game. On the right side of the screen is a heat gauge that tells the player how hot the laser gun is. If it overheats, then the player must wait about 15 seconds until it cools down before shooting again. Shots must be planned intelligently and fired accurately, or the game won't last too long. After the player clears four screens, the mothership descends from orbit, and the player receives bonus points and more fuel.

This is one of the sore spots in the game. Probably because of memory limitations, it is necessary for the program to access the disk at this juncture. It slows down the pace somewhat and seems to interfere with the flow of the game. After the docking, new screens appear and the fun continues.

The graphics in Threshold are tremendous. The first alien screen is filled with bird-like creatures. Their wings flap and they rapidly drop bombs on the player. The animation is flicker-free and smooth. Rumor has it that there are over 20 different screens in the program. I have only been able to see about six of them, and all are fascinating and original in design.

The only major complaint I have with Threshold is that it is too difficult. After many hours of play, it's still very hard to reach the higher levels. So if you'd like a challenging and fast moving arcade game for your Atari computer, then Threshold is it!