Yes, these games are extremely addictive. (not necessarily for everybody)
I am using CenturyLink modem C1000A. To block Clash of Clans, just create a new service; give it any name. Specify port 9339 and use this new rule for the device that you want to block playing CofC. Restrict scheduling for all days or enter time of day restriction. Apply.
That is all.
VEK
