I have my wife as a friend on Facebook, She sends me game requests on Facebook but I do not receive them at all. We both have checked our settings thoroughly. All the other Friends and Family of ours' are receiving the Game Requests. I am able to see her other activities - it's just the Game requests of a particular game that never show up. I have contacted Zynga and they said that it must be a FB problem.
You may have blocked that particular game/App. Unblock it here: https://www.facebook.com/help/?faq=121070141307903