We're happy to announce that we've just pushed an update to The Last Stand: Legacy Collection which resolves an issue where crouching while changing weapons would quit the game. Because CRTL is crouch and Q switched weapons, doing both at the same time would trigger the default Windows "Quit Application" keyboard shortcut. Sorry about that.
To resolve this issue, we've made the shortcut to quit CTRL + F4 instead. Now you can crouch and change weapons to your hearts' content without exiting the game. Next level stuff, folks... :)
We appreciate your feedback on this and your patience while we got through a solution.