This guide tells you how to remove the issue of not being able to exit the game by selecting the Exit button on the Title Screen. If this does not work for you, check in the Discussions section of this game for more solutions.
How to Fix
1) First, go to the actual file that runs the game:
~Steam/steamapps/common/Machine for Pigs/aamfp.exe
The Steam folder should be in Program Files (x86) if you are using the 64-BIT version. Otherwise, it might be in the Program Files folder.
2) Right-click the file and select Properties, then the Compatibility tab.
3) Check the checkbox for the “Run this program in compatibility mode for:” and select Windows 8 in the dropdown menu (I haven’t tested the other options for the dropdown menu, so it might work for the other options.).
4) Open Steam, run the game, and notice that you can now select the Exit button to exit the game.
If this guide worked for you, congrats! If it didn’t, you might have to search in the Discussions tab of this game for more solutions to this problem. If there are some things in this guide that aren’t accurate, comment down below the corrections to this information, and I will be more than happy to change the information present.