Hey there! Thanks for your detailed post. I'm sorry your system crashes and I unfortunately have no idea what is causing it. I don't have a linux system myself and have no ability to bug-test it unfortunately. I hope it's playable enough for you and that it doesn't cause you any big issues except for the freezes, but will unfortunately not be able to bugfix anything.
Thanks for showing interest in my game though! :)
Like I said at least the game works and since my post I have done further testing and it seems you might not be at fault here ...
I'm migrating to Ubuntu 18.04 tomorow ( I was still on 16.04 for video editinng reasons - some of my plugins were not back on 18.04 just yet hence I waited before migrating ) and if my testing are correct the NVIDIA drivers for laptops on 16.04 were the problem not the game .
I'll be sure to keep you posted and also update and edit my original comment should my suspicion showed to be true.
Regardless I'm amazed that an Unreal Engine 4 based game worked that well and was that correctly put together on Linux (sorry but once I'll make my video about your game that single audio stream thing will get mentionned you have no idea how annoying that is for linux gamers when devs are not relying on SDL mixer and UE 4 shits out a ton of audio stream at random so you'll receive praise for at least that ;) )