Is There Any Way To Fix Cosmetic Damage On A Gameboy Color Plastic Shell?

SOURCE: Replaced Gameboy advance SP Shell

you might have accedentally shook things up or the insides are just about gone. the shell is just a look you need to get it repaired it sounds like

SOURCE: replacing gameboy advance sp shell

Try this website http://site.powergamingparts.com/repairGBAsp.html
I've replaced shells on the phat ds and it was fairly easy. This doesn't look nearly as complicated. It should be quick and easy.
The only thing I would say is be sure that you are careful with the cables. Make sure you lock them in right. Also, sometimes with new cases if you are having problems getting the metal thing back into the hinges, it is helpful to get a small flathead screwdriver and carve off some of the plastic inside the hinge opening (be very careful). Sometimes there is excess plastic that makes the hole too small for the hinge to fit through and this ensures that you don't scratch up the outside of the case while trying to get the hinge back in.

SOURCE: NINTENDO DS BROKEN "PLASTIC RING HINGE"

nono no dont my ds had the same problem it will work as long your extemely careful but if you drop and a hinge missing the top screen will break and it is unfixable i have tried

SOURCE: Game boy color game won't play

You cant fix the cartrige as you will break it
overall its time to let go of the game boy color games try getting a DS its much better but back to your problem... IT IS NOT THE CARTRIGE!! your game boy will not accept the cartrige because of the mechanics in it deteriorating

SOURCE: i just replaced the shell on my gameboy advance

test the battery.