Gapper

Gameplay

The player controls the gapper, a sprite that travels along the lines of a grid of rectangles, changing them from blue to red. A rectangle that is completely surrounded by red lines becomes lit, and the player scores points and progresses to the next level by lighting all the rectangles on the grid.

While the player attempts to accomplish this, the gapper is being pursused by the seeker, a second sprite that moves along the grid, always moving along the most direct route towards the gapper. If the seeker overtakes the gapper, the gapper is destroyed, and the player restarts the level with one fewer lives. The gapper has one defensive mechanism. It can leave a temporary "gap" in the grid that the seeker cannot traverse, allowing it to put distance between itself and the seeker in an emergency.

At higher levels, the game plays faster, the grids contain more small rectangles instead of fewer large ones, and many grids have irregular shapes with several corners. Because the game runs faster on faster computers, a motherboard-slowing utility is necessary to make the game playable on modern computers.

Tactics

At higher levels, the gapper and seek move fast enough that controlling the seeker's position becomes paramount. One successful strategy is to charge towards the seeker, turning away at the last opportunity, so that the seeker ends up directly behind the gapper. At this point, the gapper is safe from the seeker as long as it keeps moving; to accomplish this, the player must key each turn before reaching the edge of the grid. Timing, especially near the grid's corners, becomes paramount.

Under this tactical system, using the gap is worse than useless: placing distance between the seeker and gapper comes at the price of losing direct control over the seeker, and once the gap closes, the seeker will likely approach the gapper from an unexpected angle and destroy it.