Arcade Game: Nebula (1980 Data East)
A shooting 'em up where you control a ship having to shoot and destroy alien ships. The names of the enemies are, Rava, Canda, Munda, Naga, ad Garda. Each one is worth a different amount of points. The first enemies to appear are Rava, Canda, and Munda. They will make their formation and start attacking. Naga and Garda will show to join together as a team. Canda and Munda will start spinning wildly after the player shoots them down. Extra points are awarded for shooting them again to destroy them.
Released in December 1980.
Note: Used invincibility cheat after down to last life. The game is endless. I played as far as I can. I quit after seeing the score reset to zero afterwards. There's no point in continuing after that.