Make that old ass musket from MGS4 and PW that has like a 1/10 chance to summon a MASSIVE tornado but is slow to reload, does minimal damage and is generally a bad choice
speaking of metal gear, a HF blade would be really rad.
in terms of old weapons that kicked ass, what about some of the guns from turok that aren't the cerebral bore?
consider a gun that you charge with loving SUNLIGHT?
How about GOD HAND style fists weapon with ass kicking 6 step combos and enabling the use of "duck dodging" (which is sort of already a thing, but it needs to be a lot faster)
What if we had some guns from Tribes? blockland's game engine comes from Tribes 2 anyway (which is why we have the original skiing, how about that stuff) just port the damage and projectile speed as well as any other values
forget man, there's so many ideas
You're one of the best unique weapon makers we have right now, we seriously need more of em