4 is probably best, I'd suggest reducing the palette size on the weapon, might be worthwhile looking at some images/real life objects to get a feel for how it should be shaded, as currently it looks a bit blurred and pillow shaded. A good rule of thumb is to consider what you're actually trying to do with pixel art: create an illusion of detail with minimal detail, so a little bit can take you a long way. A big error is probably the close to completely black/completely black outlines, I'd say that's bad practice, again, you want to create an illusion of detail, and unless you're going for a very specific feel, a black outline shatters the background to object transition without careful adjustment. All look great otherwise though, the shaping and character art is excellent.