Check the number of stars in level "signs" on side B - 17 levels times 3 stars should be 51 stars not 54. Also check the "show solution" on sublevel 17 in level "signs"
AdminHalvard Eggen (Admin, DragonBox) commented
Thank you for your feedback.
We truly appreciate your effort in letting us know about bugs like this.
The bugs you mention will be fixed in the next released version.