Some problems I noticed with your covers...
-The UPCs are incorrect for all the covers.
-Why are the game title logos repeated twice on the fronts for Battletoads and Battle City?
-The part numbers on the fronts of Battletoads and Battle City are incorrect (it's actually the part number for Super Mario Bros. 2 on the FDS)
-The publisher logos and information aren't on the spine or the back of the cover; for example on Holy Diver, it should be "(C) 1989 Irem", not "(C) 1989 Nintendo"
All great notes. The short answer is I'm just trying to put some covers together for Japan only games that I'm hunting down and want to box, covers don't exist, and I'm not exactly a pro photoshopper or cover master here. Just sharing my own personal work for Famicom covers.
Here are some longer answers:
-Not too concerned about UPCs. Nobody will be scanning these and I have no way of knowing what the actual numbers would be... so I just didn't bother, but it looks official so I left it on there.
-Title logos repeated because I was trying to keep to the template as well as the devil world cover posted before. And since the artwork is pretty small I didn't want to remove the top bar but didn't want it blank either. The top bar helped cover up the lack of large artwork and blend it into the template, so I wanted something there.
-Didn't quite know what the part number was, but like the UPC, it looked official to me.... If you have a way of knowing the actual part numbers for Battletoads, Battle City, and Holy Diver (or even Devil World), let me know.
-lastly, makes sense, just didn't even give it a thought. I'll change it!