after i instaled the game, it said that it was a GB file. i haven't seen those before, so i did some research.

and this is what i find: "The Genbank format allows for the storage of information in addition to a DNA/protein sequence."

and now i am very confused. so can anyone please tell me how to open it? because i thin i found the wrong GB format lol.

This is a gameboy game. You'll either need to play it in browser here, or by using an emulator. I recommend Sameboy! 

If you have the means, you can also flash it to a real cartridge and play on an actual gameboy/gameboy color.