Doom was configurable like that with a tool called Dehacked. I remember mod packs for the tool, doing things like "mine layer", which set the rocket speed to 0

Doom was configurable like that with a tool called Dehacked. I remember mod packs for the tool, doing things like "mine layer", which set the rocket speed to 0 and made it cloaked, so that you could lay a minefield and then make the monsters walk into it. Or make the rocket launcher shoot lost souls, make chaingunners fly and many many more.