Pokémon Battery Replacement issues Game boy Color Cartridge

I recently bought a Pokémon game on eBay , battery was missing I tried to put a new one but one side had nothing for me to solder into. On the other it has contact but on the others there’s no contact, it is still not being able to save.

Can you send a photo of the pcb of the game boy cartridge. It sounds like you’re missing a pad for the solder to be applied to. If this is the case, you may need to grind off the masking around the missing pad to expose the copper on the board and then solder on some copper tape or something similar to make contact between the new exposed copper on the board and the the copper tape you are using as replacement for the battery pad. If you look up missing battery pad gameboy cartridge on YouTube, some videos may turn up.