Icy and I discussed the Smelter over IRC (a bit before he posted this version online, actually...), and my opinion hasn't changed: it's a cool weapon, but it occupies a niche already partially filled by two other weapons (Nailgun and Flamethrower, primarily because of the ripping behavior) and replacing the Claw with it would muck up the ammo distribution (since it wouldn't make sense for the Smelter to use Souls as an ammo type

). I'd maybe consider adding it as a Slot 8 weapon, though, if people think it wouldn't be overkill to add yet another weapon to the set (which I feel it probably would).
I did implement a portion of this for the Dark Claw's primary fire that makes it a lot more interesting: the projectiles now bounce a few times (twice, to be precise) before exploding, making them much more seek-happy since if they miss the target they can rebound and zoom in for a second strike. That and the projectiles are a bit stronger -- 15 damage as opposed to 12, making it slightly more powerful than the plasma gun, as it should be. Not much I can do about the sprites though unless someone draws new ones -- am I the only person who doesn't find them totally unfitting as-is?

Regarding the Machinegun, I'm not too keen on it. It's literally just a weaker chaingun -- at least the Rifle's behavior is a bit different in terms of accuracy (and, maybe in the future, semi-auto-ness).
Furthermore, did you already put it in the wad? That could muck up merging the resources, especially if the Doom editor numbers are different. I don't really want to add smoothweapons or improved existing effects either -- they just add fluff and I really don't want to mess with possible mod compatibility by messing with the existing weapons if at all possible. I guess I wouldn't be opposed to (or mind putting together) an 'HD Effects' accompanying wad towards the end with all that stuff, sorta like what DBThanatos did with UTNT. Just not now.
Forgive my over-concerned nature about the resource merging. It's mostly my fault for being late with the resources, but this sort of situation is what I'd hoped to avoid in the first place.

Anyhow, I'll post up a new version tonight and see if I can work with Malinku to get the stuff merged. Still no Soulrender yet (curse my slowness) but there have been some misc. changes worth updating for, particularly the new Claw behavior and the fact that the Nailgun now has its own ammo type.