thank you all for your feedback. Originally I planned to create this game for tablets and smartphones. But now I modified it to run on pc´s, thats why there is such a big border. Don´t know what to do about this right now, But I will find a solution. swapping x and y is maybe a good idea, thanks.
Currently the game has about 50 levels and a good player will only need 3-4 hours to play through it so I will have to add some extra playtime for sure...