Warning about Avast antivirus
One player reported a strange problem to me in which the game failed to start at all. I have now finished investigating this and it turns out Avast antivirus blocks execution of the game silently without alerting the user. Further investigation shows that it does this for any project I build with Unity 4.7, including a completely blank project, if I include an icon (!). As such, this is an Avast bug rather than a King Machine bug and I can do nothing about it.
Avast users can still play the game without problems, but will need to first add the game as an exception.