A nice looking game.  Unusual layout, is that a flipper up the top left?

What's the "Rock-a-rock Punkte" on the BG? 

Web translations lead me to credits - does it award free games to individual players? or is it for matches on a per player basis, which wouldn't really seem necessary? For that matter credits on an individual basis wouldn't really seem needed on a per player basis unless there is some really weird way of winning them, and then how would you claim them or how do they reset?

In the words of the no so great oxlymoron "please explain"!