Spider Fighter is an arcade-style action game similar to Space Invaders. The player controls a bug blaster at the bottom of the screen, and needs to defend the three pieces of fruit at the top right of the screen. Various types of attacking spiders scurry around rapidly, trying to destroy the blaster and steal the fruit. If all of the fruit is stolen or the player loses all of their bug blasters, the game is over. When all the spiders of a round are destroyed, the player moves on to the next, faster round. If the player still has all three pieces of fruit when a round is completed, they will receive an extra bug blaster.
The gameplay in Spider Fighter involves shooting and dodging incoming spiders while protecting the fruit. The player must use their bug blasters strategically to take out the spiders without losing any fruit. With each level, the speed of the spiders increases, making it harder for the player to succeed.