You are a lone ship in a world of marauding robotic enemies. Each level starts off with you sitting alone, but soon the robots start closing in on you in greater and greater numbers from all sides. Your job is simply to mow them all down while you try in vain to avoid both their shots and their sheer numbers.

There are five different types of robots, some requiring more than one shot to kill. Once destroyed, each robot leaves behind a little tile with a number. These tiles are very important to the game for several reasons. First, by running over the tiles, you get a large bonus -- generally 10 times the score you got for killing the robot in the first place. And second, the tiles absorb your shots, meaning that its also worth collecting them in order to clear a path for killing more robots. Finally, the tiles are not permanent, so they will disappear after a few seconds.

Each level has a timer which counts down. If you destroy all the robots before the timer hits zero, you get a nice bonus at the end of the level based on how much time was left on the clock. If you don't make it in time, a giant mothership comes in and aggressively finishes you off.

On most levels, you start in the middle and the hordes of robots move in from all sides. But every fourth level there's a bit of a change: a Galaga-like shooting arcade where high-point robots dance in a pattern instead of relentlessly charging your chip. Unlike the Galaga bonus levels, the robots still shoot at you, but the points you get for blowing up all the ships (and collecting all those '5' tiles) are a big win.

In the end, the key to getting a good score in Nova 2001 revolves around the tiles. The level ends as soon as you kill the last robot, so it is worth saving one robot so you have time to collect all the high-point tiles you can before the level ends.

A second joystick. The similarities between Nova 2001 and Robotron are dead obvious as soon as you play it. Sure, there are other elements which affect your strategy, but the fundamental structure of the game requires you to be able to move in one direction while firing in another.

UPL's solution to this problem was to add a second button, next to the fire button, which locks your firing direction while you hold it down. Although this does allow you to keep a continuous stream of bullets flying in one direction while dodging incoming robots, it is really a handicap when you have multiple large groups of robots hitting you from all four sides.