Caverns of Mars is an exciting, fast-moving adventure game for the Atari 400 / 800 home computer (for now, it is available only as a computer disk program). The game plot is simple. The player must maneuver his one-man fighter down into the depths of Mars, activate the timer of a fusion bomb and escape before the bomb goes off.

The game starts with the selection of one of four skill levels, Novice through Commander. Instantly, the fighter (very reminiscent of the fighters flown by Cylon raiders in the TV show Battlestar Galactica) starts its descent into the deep Martian cavern. The speed of the descent and left-right motion of the fighter are controlled by the joystick, while the action button fires the twin wing-mounted laser torpedoes. The game graphics are quite good, with both the fighter and the scrolling accomplished smoothly and clearly.

Depending on the skill level selected, the player must penetrate two to five different caverns to reach the bomb. The first cavern has no defenses but winds treacherously. Its walls are lined with rockets, radar installations and fuel tanks - targets for the fighter's lasers. Hits score points and the destruction of fuel tanks adds to the player's fuel supply. The fighter can't carry enough fuel at the start to complete the mission.

In cavern two, the fighter must blast and weave through waves of missiles. Some are rockets, others (in red) are fuel carriers. Cavern three boasts laser gates - fiendish devices that flash lethal energy across the entry channel. They are immune to the fighter's torpedoes so they must be timed and sped past. Cavern four is the home of deadly space mines, white diamond-shaped objects that jump around while trying to explode against the fighter. These can be either avoided or shot but neither defensive ploy is easy, as their movements are unpredictable. Some of the mines are invisible at times, making them even more dangerous.

Only on the Commander level does the fighter have to pass through Cavern five, which is actually a maze-like section of a Martian city. It is especially treacherous, requiring incredible dexterity to navigate, plus split-second timing to destroy the fuel tanks that block the way. And, of course, getting to the bomb is only half the job. Getting out safely requires a highspeed back tracking through the same mazes and winding cavern walls, though there are no rockets, lasers or mines to dodge this time.

Regardless of the starting level, you get five fighters to complete the mission. Contact with a cavern or city wall or anything else on the way up or down, or running out of fuel, costs you one fighter. When you lose one, the replacement starts the mission back at the entry to the cavern even if you were only a hair's breadth away from the exit when destroyed. This can be particularly frustrating when you are learning to play and find yourself having to fly the same segment of the mission over and over.

The one disappointing aspect of Caverns is the conclusion. The reward for a successful mission is the display of the points you accumulated and, after a nerve wracking game, that's a bit of a letdown.

Some laser gates have multiple beams. The only way through them is one at a time. Pause between them as they flash on and off.