Star Crystals

The player controls a small spaceship that can move in all directions, and can fire vertically left and right. A shielded enemy space station sits in the center of the screen, with a small core inside. An enemy spaceship moves laterally on the bottom of the screen, and if the player shoots it, the enemy ship moves into the larger base, and the shields drop. The player can then shoot the core for bonus points. The player has limited fuel. Fuel items drop from the top of the screen, and if the player shoots them, their fuel stores are increased. The player starts with 3 ships, and it's game over when all are lost. There are 3 levels of difficulty.