I see a list of games dev'd in Hungary, but it requires filtering, because i see Battlestations: Midway/Pacific there, for example.
That list made me remember one awesome gem - Scarabaeus, a great FPP-puzzler, but that was on a C64. I see Reunion was also Hungarian.
Take a look Yourself: http://en.wikipedia.org/wiki/Category:Video_games_developed_in_Hungary
But i seek hidden treasures. I bet there are some, every country has them. :)
Battlestations: Midway and Pacific WERE developed by Hungarians, I recall game mags mentioning this fact.
I sure don't know of any hidden gems developed here... But then again, I don't know THAT much about Hungarian developers. I know of someone who must have more knowledge on the matter (an editor who writes the retrogaming article for PC Guru, a Hungarian game magazine), but I'm not sure he is on GOG. Or better, he's proabably here (he's aware of the site, he's mentioned it in the past), but I don't think he frequents the boards.