The cat returned! After several optimizations and clean-ups "it" returned on screen. The player moves now at a minimum base speed like in Tiny Wings or other runner games. BTW if you haven't checked out Tiny Wings, go and have a look for it. It's really cool. Jumping works now as expected. You can only jump if the player is on ground. It's not as easy as it sounds... The physical player-body in box2d slightly jumps and falls off / on the terrain. Therefore the player won't accept the jump action because it's often above the ground and not 100% on the line. I used a sensor for this which gets attached beneath player's body, inspired by this posting on box2d's forum. It works like a charm. To make a long story short, here is the uploaded YouTube video.