sometime I put the fish on the penguin head,but top penguin not move. Is this a bug?

Demo starts with three white figures and when you try to select level it`s just return to these start sequence ! Downloading didn`t start direct and and in t the end it stop`s on 99% for a minute before the last % was added !!! Never happen`s before with other demos !...

Is this level beatable in the demo. I sit for halve an hour on this level now and have no idea. Seems like there is only one to two options per step and if there are two, one of them is a guaranteed dead end. Like the demo pretty much so far but this level i can't beat. ...

I've cleared 1-9 and three optional levels in world 1. How do I unlock world 2?

Is there any visual clue in the level select, if a level has been solved by you? I think I solved all levels, but I can't really see, if I have forgotten to play any.