My kids love this puzzle too.
I am considering rounding the corners of the axles/pegs so that they can pass through and line up on the other side of the box more easily. That seem to be the most difficult part for me, just getting them in the other side of the box!
I like the acrylic version too! I was thinking about making the box clear, but that would remove some of the complexity of the puzzle. It would look awesome though…