Awesome!

I finally got to see your fireworks display!

Loved the cool travelator moves, especially on the right side.

This one really had me stumped all day!

If it wasn't for your opening spoiler I would still be stuck.
I had been pushing the metal boxes in the upper right part instead of the lower section where the sign was.

I did complete it without using one metal box on the left side.
Though I sank it elsewhere for purposes of the ending.
Also I never touched the boulder, so I'm not sure what it was meant for.

Here's what I did on the left side:
I pushed the wood box down first, used the travelator to fetch the coin on the right, then sank one metal box below the wood box.