I can only describe what the game was:

You play as some "space janitor" who's job is to clean out space debris and other hazardous waste from some sector of space, and also fight off hostile ships that have their sprites stolen (or the other way around...?) from the Rex Blade series of FPS games. Even the projectile sprites were from those games I think.

There's only a full screen HUD and no stylistic cockpit, the physics in the game were really basic as well, certainly nothing like Wing Commander but it worked.

I have no idea if this was a shareware or a freeware game, given the sparse content and repetitive gameplay I'm leaning towards freeware.

I remember it having fully digital music but I can't remember if it was module based, maybe the game used MikMod for sound support?