I know this isn't the easiest thing to sort out, but it would be worth going over the weapon sprites and updating their visuals, as currently they are not cohesive with the vanilla weapons or even with themselves (some weapons have 32x32 sprites which stick out like a sore thumb while others have very unappealingly low quality sprites - such as the katana).

Tinker's Construct does a good job of showing what's possible with 16x16 sprites, it should be manageable to keep them all within that resolution.
Hope this can be considered as it would make the weapons far more appealing and blend better with the game, thanks!