I remember playing a side-scrolling, platforming shooter game in the mid-90s, that was a direct knock-off of the Doom trademark.

It was actually pretty well-made, as far as I can remember; the graphics (original sprites, not ripped ones from the game) and gameplay (quite challenging) were both decent by their own merit. The only caveat I can think of, was that the only projectiles being shot were little white pellets (which made a distinctive popping noise when fired).

I think it even seemed as if it was created in a customizable game engine, and that I had both looked, and had a hard time finding any info about the engine, despite that I may have gotten this game from AOL's prolific Mac download library (rest this aspect of AOL's metaphorical soul, for helping to make my childhood).

Anybody else know about anything like this?