Just a thought: Old Unity engine versions had problems with non-English locales, often leading to completely random problems. Could you try to start the game by prepending `LANG=C LC_ALL=C ` and check if that changes something?
Wow, unbelievable, thank you so much ifo and SebastianPetters... if there's anything I can do for you to thank you, let me know. There will be another patch this week or next week, I'll make sure this is included.