try to go in contact with the developer.
Have the same problem with one of my downloaded apps not workin correctly. Guess it´s because of the 4x size of the Retina display. Mailed him but havn´t heard back from him. Guess he is not doing working on Apps anymore because all of his releases dated from 2010.
But at least you can give it a try. I had nice conversations with other developer who support their products.