I don't think that I've ever encountered a game quite like Operation: Inner Space.
Okay, it's a top down space(-ish) shooter, and there are others like that.
Except that the "space" is small, and wrap-around, and there are multiple of them, and they're each a folder on your actual computer. (I daresay that you didn't know that your computer was full of stars. :P) And you fly around fighting viruses and collecting resource files.
Meanwhile, there are a number of NPC ships, each with their own faction-allegiances and behaviours. Some of them are teddy bears. Some of them are cops. And yes, you can fight them, too.
The exceptions to this are a selection of folders that, instead of being open fields, are racetracks. Here you can challenge NPC ships for a resource-prize!
And amidst all of this, sometimes the "Inner Demon" sucks you into the swirling vortex that is its domain, bounded by four dragons and the sparking orbs that they protect.
Overall, Operation: Inner Space is bold, and neat, and really really fun to play.
I recall that I had the demo on a magazine cover-disc once upon a time, and fondly remember playing that demo over and over again. ^_^