Well, my problem was crash after 15 minutes of play. That however is hard to explain because I can't even say what caused it. Version 0.6c contains way too many things, connected to each other, witch honestly make game quite confusing since many things aren't explained yet. All I did was dig dig dig and build random stuff after. The reason why I hope the Demo released on Steam will be more detailed is because game looks a little bit over-complex'ed with lots of misc things attached to everything, so if Demo will contain only small piece of the game it will still remain confusing as it is in v0.6.
Best way of reporting crash.
Hope it will help.