Although it doesn’t look like much, Spore is in fact a high-tension, high-speed, single screen Gauntlet variant, with lots of shooting, shooting, shooting!
You’re shooting spores, so it’s okay, and they come thick and fast.
Generators create more spores, so taking those out first is good. Fences hold back most of them, but to finish the level you need to open the gate. A torrent is coming!
Spore even has a simple level designer that is easy to use and start jamming with.
Spore is a great, semi-obscure, gaming classic first released by Mastertronic in 1987.
More: Spore on Wikipedia