It came to our attention awhile ago that there is a bug that occurs with some users that prevents the difficulty selection menu from popping up after selecting your crew. After extensive testing we can't seem to replicate or find anything that might cause this.
So to help out those users that do have this problem, we have put in a cheat to skip the difficulty selection menu.
After choosing your crew hold LEFT SHIFT + C and then press 1,2,or 3 to play on casual, normal, or hard difficulty respectively.
DO NOT use the cheat before selecting a crew, as this may cause you to load in without any colonists.
Hope this helps!
Cheers,
Cameron