Broken Mario Tennis (GBC) Please Help

Hello. Recently I have received a broken copy of Mario Tennis for the Game Boy Color.
When I got it it was not responding to anything. After hours of cleaning, battery replacement, and hard work I was able to get the lock out chip to respond. This response, however, seems to be random and as if the lock out chip (which I am not sure exactly which chip it is) is loose. The "Nintendo" logo will change without removing/moving the game or unit just by resetting it. In the occasional chance that the Game Boy confirms the game, a blank screen appears. I have recorded a video of the problem which can be seen below.



I tried the cart on a Game Boy Color, Game Boy Advance SP (2), and a Game Boy Pocket to see if the warning would come up (which it didn't). When I got it the security bolt was rusted on and the entire unit appears to have been in water for an extended period of time at some point.

Any ideas? Is it fixable? Thanks.

 

Would I be able to see a picture of the board so I can check the traces?

 

Could be bad traces or real bad water damage. chances it could be fixed are slim if its water damage if you ask me. its a shame seance this is such an amazing game.