The gamekey utility is kernel dependant, it's not a standard apk. The gamekeyhelp.apk I was talking about it's just a visual app that shows hot to use, but must be implemented in firmware, it's not a stand-alone apk.
But i agree, it's weird that they didn't include it having in mind that s601, s602, s5100, s5110, even the old v5200 include it. All of them basically except s7100. I don't understand why.