Oh, fun! I especially love the mace, you've done an excellent job of defining it without it all being visible, you clearly understand the object in a 3d space and how light would work on it. For just the mace, the only improvement I can come up with is defining the points of the spikes a little better. The outside ones having one more pixel to square up the corner, and all of them having the highlight at the tip or along the center line instead of around the base.
I think if you want to improve on this one in general, you need to look a bit closer at being picky about the details. The line on the arm makes sense if you've got the original to look at, you can tell it's the tatoo. But if you hadn't seen the original, that line is just something that makes the arm hard to understand. It looks like strange large dent, maybe not even on an arm, maybe it's a scarf. Without that line, the fact that it's an arm becomes clear again. That detail is getting in the way of the picture. There are lots of other places like this and I think it's the reason behind why you keep getting orphan pixels, you keep trying to include details that are getting in the way. On the other hand there are other places where the details are more important, and this is where exaggeration can come in and help out. The belt buckle is a good place for this, you could have a nice bright c shape surrounded by the black and even though that makes the buckle much, much larger than the original it won't look out of place. This is why it's important to switch back and forth from zoomed in and zoomed out when working on pixels you need to see if it works or not at a small size. If it doesn't, cleaning it up will make even the smaller size work better. Well, most of the time, anyway. If it helps, some art programs let you have multiple views of the same piece, so you can have one at 100% and one at 600% or whatever you like to work at.
Overall a fun and dynamic piece that has some of your own personal flair added in. I can tell that you're working hard to implement everything you've learned into this one, and I think it's stronger for it.