You're looking at the front and back of a '15' puzzle. Either side is solved if each line radiating from the center of a tile finds a match. There are 652 solutions in two classes, 326 in each. Front and back are always in the same class. Crossover from class A to class B is possible by scrambling the puzzle or by choosing from the four 'trivial solutions' in the pop-up menu. Within each class, the puzzle behaves regular.
There are exactly four more meta solutions! They are distinctively non-trivial. Find only one, and all will appear in the pop-up menu. If you have downloaded BackSlide as a package, you can also make the full pop-up menu permanently available. Read all the details.
To make things easy, you'll find all 652 solutions in the Slide Show below. Rotations and reflections are not equivalent in BackSlide. Number 30 for instance is a rotation of A1, but it will not give a meta solution in BackSlide.