Enter this in the launcher to play the game:
Email: free@grapplinghook.de
CD-Key: 5Q2CW-PLX3E-2T2R1-61SPH-NZ13P

Download the full version of Grappling Hook:

Windows: GrapplingHookSetup.exe
Mac OS: GrapplingHook_Mac.zip
Linux: GrapplingHook.tar.gz