Glad you enjoyed it! Well the turtle is the only real "cross-area" puzzle. Technically you can use the turtle at THREE(!) different spots to get into the human area haha. Since you like sliding puzzles were there any parts you didn't enjoy as much or were there any parts that stood out that you liked more?
Well, the only part of the game I had any issue with was the turtle, and that mostly came down to either not knowing where he should go or not knowing how to get him to a particular spot. The thing I did find interesting about this game was the use of multiple spawn points in a room being vital to solving each puzzle. At first I thought a few of these puzzles weren't possible, but finding out you keep your spot just outside where you enter a room and that the room doesn't reset made for some fun "Ah Ha!" moments. I don't know of any other tile sliders that use that.
tl;dr The turtle's usage felt a little vague. I liked that the puzzles weren't self contained and literally had you come at it from different angles.
Edit: My favorite room was probably the first giant bug room. That one has some clever movement.
Hi! I'm glad you enjoyed it, the Turtle part was confusing to more people, I changed the game before you played it I think so that he tells you if you aren't strong enough and need to eat more, and the "T to flip" instruction was hidden until after you flip him over the first time. Before this update it was very confusing what you were supposed to do. So I'm happy you only had a problem finding where to use him.
All the puzzles can be solved without dying, but resetting the progress on death would have required a lot of extra work and would probably have made it a lot more frustrating to progress. Though there are some puzzles where you need to leave the area to either reset the enemy position or enter from another entry point to get everything. I was inspired a bit by the world design in legend of zelda in that you "come back here later", like you get to see the city walls and gate pretty early, you also get to eat a wayward sheep before getting into the human area and you see a farm with some farmland as well that you get back to later to destroy. The purpose was to create anticipation through teasing future content.