Wormhole

This is a clone of the arcade game Gyruss, where the player controls a ship that can spin around the screen in a circle and fire at ships that rapidly emerge from the center area of the screen. After the first level is cleared they will start firing at the player's ship, and there are also two ships that appear later in the game that creates a force field in between them (which shooting one or both ships will disable the field), along with an indestructible asteroid that emerges from the wormhole.