I have a hacked 3ds with retroarch, have gotten psx games to run on it so I'm not totally lost. I also have my neo geo roms on .zip format. I just can't get them to run. What core do I use? is a bios required? (can't remember if I got one for the psx games, it was like a year ago), do I need to convert the games to other format? Explain like I'm 10. Thanks. Also, tried some injects, but the screen it stretched by default, can't remap buttons or set autofire for games like metal slug, so that's not an option anymore.