Just got to the end :) I really liked the various additions over the course of the level sets, and things get really interesting once you're juggling the properties of wood, sand, pits and metal!
It might be because of the post-jam extras, but I think the difficulty curve is slightly erratic, with some of the later levels appearing to telegraph their solutions. However, it's possible that I'd finally just grasped the mechanics by that point! Pit 10 was probably the hardest level for me, but perhaps because it's easy to stray far from the intended, deceptively straightforward solution.