I may be misreading the section on light rules but where it says "If any of your dice ever shows a 6 or you fail on 3d6 the light goes out." this is implying if you get over 4 on 3d6? It's never explicitly stated that over 4 is a failure except of course when a 6 is seen. Could anyone confirm if I'm understanding this right? 

This is correct, although in the next iteration of the rules I'll be changing it to:

• Check every other Turn rather than every Turn
• 4+ is a failure and increases the die size or extinguishes the light on 3d6. No automatic failure on a 6.

Thanks!