OK, this thing is totally messed up ... I hit a shot over 4000km, and I have a screenshot to prove it, but it hasn't given me more than the 750km achievement ... wth???
Haha, awesome ... the most obvious answer isn't always right ... though sometimes the answer is so obvious you don't even consider it ^_^
Clues aren't "obvious" ... but they're there ;-)
 "Gravitee"){kind=icon}
 "Casual Gameplay Escape"){kind=icon}
 "Terrascape"){kind=icon}
 "Snotput"){kind=icon}