Interesting twist on Sokoban which makes you think about when to place stuff, I think the first level shows how this game is unique compared to the second so I would have recommend to make it the opposite, showing the second level first as this is just a sokoban level and then planning levels on the idea that as soon as u insert something you can't move it again.
Also, would recommend if you are going to expand on it is to add an undo button :) overall great job :)