Are you running a 32-bit version of Windows and experiencing crashes, sometimes during specific area transitions?
This seems to be caused by the game at certain points needing more available RAM than Windows in 32-bit will allow, so it will crash. In fact, this happens in other Unity-based games, such as Wasteland 2. One workaround customers of Wasteland found was that you could change a setting that would allow applications in Windows to use more RAM on 32-bit Windows.
We do recommend setting this flag if you are experiencing these crashes, but please understand that this is a change to your computer that takes it out of its default state, and that we are not responsible for any damage to your computer that may occur. Granted, this sounds scarier than what the actual change is, but our lawyer types make us say things like that.
If you are interested in trying this, please visit the following thread:
How do I find out if I'm running 32-bit Windows?
What's the story with 32-bit Windows versus 64-bit Windows?
The good folks at Lifehacker have a great article that helps explain the difference: