You could look up Voultar on YouTube. I don’t think anyone is as good as this guy.
You may not be able to fix it though. You can’t just get a new PCB as they vary depending on the game. You’d have to find someone that already has a pcb layout design of this exact game. I believe all the game data itself actually exists on the black chips though.
In my opinion, this isn’t worth fixing unless you just want to do it for a fun project and have soldering skills.
This may be really hard to do if you don’t have a proper desoldering tool. These things are pretty small. (If you do it, don’t use lead-free solder, use flux, clean with isopropyl, and don’t use hot glue.) a soldering iron in the 40-60w range would be good for this project.
My recommendation is to try to clean the corrosion with isopropyl and maybe electronic contact cleaner. What I’m afraid of is that the game got wet and was powered on which could have fried at least one of the chips, rendering it useless. It sure looks like it could have happened. If you look under the main ROM (the biggest black chip) there does appear to be some charring and the solder joints on the bottom right don’t look quite right. Maybe it looks different in person.
On the plus side, it does look like you got an original copy of the game and not a bootleg based on the board I see there.