I think if there was some kind of indication of what the final thing should look like, or an indication if after manipulation a tile is either in the correct spot but wrong rotation, or correct spot and correct rotation, it would go a long way to making the game feel solvable, as you can have a sense of progress.
* Every tile has two orientations 0 and 180 degrees which allows to cut a lot of possibilities for small fields. * Three tiles can be flipped together, meaning if you have one or two tiles unsolved, your idea won't work out. * Large fields have more solutions.
Sadly I found some bugs:
* World generation does not work correctly: there is an unmovable field (nice idea!) but during generation it gets moved. This makes some puzzles unsolvable. The randomizer should ignore this field. * The undo function has some issues undoing the wrong move or skipping a move. Fully undoing a puzzle does not always result in a solution. If this happens while you're playing you get locked.