Those NeoGeo games on sale have really shit ports by DotEmu. I got suckered into buying all of them when they were on Humble Bundle, it’s bunch of ROMs bundled with a shitty emulator. I don’t mind that it’s just ROMs and an emulator, I’m not expecting native ports, but the emulator should at least meet some basic standards. You cannot re-bind keys, you cannot change arcade cabinet settings or change the resolution. You’re better off downloading the ROMs off the internet and playing them in MAME instead.
That said, some of the reviews on GOG say that the ports are good, so maybe some of the games come with a different emulator, or maybe viral marketers are manipulating the reviews. Either way, investigate the port quality of each individual game first before purchasing.
Good to know.