Fun game but I'm stuck – Plastiland - explore the worlds of Plasticinia, Plastipolia and Plastidonia! Review

I love this game, but I'm stuck. I've gotten all the stars in world 1 and half he stars in the bonus world, 72 in all. The problem is world 2 hasn't unlocked and I can't get anymore stars so I can't play anything else. Someone please help, is there something I haven't done yet or is that as far as I can go?
Review by Clarkstier on Plastiland - explore the worlds of Plasticinia, Plastipolia and Plastidonia!.