What you experience is called a crash and its cause can be related to many reasons. The first thing to do is to re-install the product. If there are corrupted files, reinstallation should fix it. Additionally, there could be a bug in the code that prevents you from playing. This needs to be addressed to the official developer since he is the only one who can make changes to the installation code and package.
Re-install the product and play again. If the game crashes, send an email to the developer. You can find support on the official App Store or use the official page to contact him.