I did not beat the fourth level but on the positive side it gives a good hint of how cool the game would be if movement worked properly (I won't add much to what other said, it's very slow and sometimes walking forward does not work, turning and crab-walking seems to always work though') and/or if you could easily see the directions of the tiles you're placing without closing the map (but maybe I missed something regarding this one).
The game is not really playable as is but good job anyway, the art is very good and the gameplay would be too without those technical issues.