Gray Matter wasn't made entirely by Hungarian developer. To be specific, the development was started in 2003 by the studio Hungarian Tonuzaba. In 2004, however, production was suspended and only two years later, the German company DTP, revived the project. On April 2, 2008, it was officially announced that Tonzuba had been replaced the French developer Wizarbox with the final release at the beginning of 2010. Nitpicking aside, this is a really overlooked game when it comes to adventure genre and deserves mentioning more often.
I only finished Van Helsing I and II, and they were good hack and slash games. They felt really big compared to older titles in the same genre. There are some interesting builds, and the itemization was solid. I liked the art direction and the ghost companion who is more useful than it seems at the beginning.
Thunder Wolves was another one, smooth shooter that can be finished in one sitting like an old arcade title. Sine Mora was another shooter that stuck with me, although at first hearing hungarian language was refreshing.
Other than that I don't recall playing rest of the games on the list.