Really good but I think the darks are little too washed out, maybe just some minor highlights or a drybrush of the lit color?
Not quite flat, I think the dark area needs just a tiny touch more color.
Could be the fault of the photo, thats just what my eyes tell me.
Hit it once with a thin gloss varnish then follow up with the matte so you get an extra layer and no shine
If you apply each in a single layer, it should come out looking roughly as it does painted. You can use different types of varnish/clearcoat to get different effects. For instance, if you had blood or wet you would want to go with gloss. I recommend practice with a piece of painted paper, just paint a happy face or something and try your layering. OR if you have a spare metal mini, you could prime it and practice until you can get it to look like the primer (since metal is easy as anything to strip clean)