(video games, slang) Video games from Europe (especially Eastern Europe) with ambitious concepts but lacking in execution and sometimes exhibiting unintended glitches.

as per Wiktionary (https://en.wiktionary.org/wiki/Eurojank)

I was under the assumption the Styx -devs were german, but apparently the studio is French. Either way. I also don't recall any specific glitches, but the first game has a bit stiff climbing mechanics where you can (and will) do some unintended jumps to void etc.

Basically "AA game" instead if "AAA big budget game"