Um..?

Okay so overall it is a very awesome game. Back when I used to have a computer I would absolutely and completely work to level up as fast as I could on it. Then my computer broke and I hadnt played it since. I go trough the App Store and see that this game is here so I instantly downloaded it and started leveling up. I recently completed the challenges but it says "*complete all challenges for ultimate reward"
Upon completion I expected like a pop up or something but nothing came out so I was wondering if there wen was a reward.

NerdyGuyWhoSings about SAS: Zombie Assault 3