Artoor-
  Sorry for the late response- you asked- 
I' pretty sure that I just don't see bad points of my model cause I see it every day... so can you tell me something about these "couple of things" ?
 Really, its one thing-the rail gun. to my eye, it looks...out of place. When I look at it, I see a much smaller gun ( like a submarine deck gun, or the bow gun on something like a corvette ) greatly enlarged. Its a look that seems out of synch with the look of the rest
of the ship's ordnance.  Something like a hood, or turret, over the assembly, might add to the sense of mass and presence.  
 I really like the Marlins, and the muzzle-loader is great! ( A muzzle-loading Wave motion gun, perhaps? )  Looking forward to the rest of the build!