The targeting cross-hair looks like a red plus symbol in a diamond. The player shoots from the ships in each of the four corners. You're trying to shoot down enemy missiles, ships and the missile basses on different planets. The enemy missile basses are small flashing red targets. Destroying these missile bases quickly is key for passing a stage. If you lose a ship in a stage, it doesn't respawn at the start of the next one. If all four of your ships get destroyed then it's game over.