I'm trying to block game "X" from accessing the internet including updating

I'm using OS X El Capitan and I'm trying to prevent a game from accessing the internet including blocking it from checking for updates for the launcher or the game itself.

I've gone into Security -> Firewall -> unlocked settings -> Firewall Options -> Found the game in the list and changed it from "Allow incoming connections" to "Block incoming connections" and it still goes out and finds updates and tries to get me to accept them and update the launcher and program.

In my opinion the update has ruined game play so I don't want the update until they either change it back or they fix the game play enough that I want to play it their way. Until then, I want to block it from even checking to see if there are updates. I want to be absolutely, totally, offline like there is no network cable and not wireless internet or any other kind of internet.

Since this didn't work, please don't tell me to buy another product. Tell me what I did wrong and how I can fix it with what came with OS X.

The issue is that the firewall option stops connections from outside to the app but for an update the app initiates the contact to the suppliers server so the firewall does not help here.

the program Little Snitch does allow you to control the app starting a conversation with another IP address and so can do what you want.

As mentioned, Little Snitch is the ultimate solution here allowing you to identify and block all connections. If that's a little heavy-handed for you though the Radio Silence app offers a simpler way to block specific files from connecting.