I really like the foundation you have here, even if the gameplay doesn't quite work for me. I ended up quitting at Tutorial-6, but I see a lot of potential in the system you have built. I think the interface, graphics, and sound design are all solid.

How to expand the game:
- In my mind this is currently a memory game (just memorizing the sequence laid out before you) rather than a puzzle game, and I would much prefer a puzzle game. Watching a sequence and then having to remember it to rebuild it feels extremely tedious to me. I would prefer the challenge to be in achieving a certain end state using the modules available.
- If your intention is for the game to be a memory game, I think you're well on your way, and my only suggestion would be to keep all modules available after they've been unlocked (whether or not they're needed for the current sequence) as it would increase the difficulty a bit.
- I also second Wandering Peak's idea of including syncing machines!

Possible error:
- "RMG_A is a command console for head part"  should that be RMB_A?

Huh, the job of a machine programmer of machines is hard :-) I did it up until the idle commands and decided to make a break.

It was interesting and captivating. At the same time, it would be more engaging for me if the puzzle process was spaced out with some scene changes and some story maybe. It depends on your target audience, of course. Many people enjoy puzzles only for the puzzles themselves.

Have you considered setting the task of syncing the work of two such units? Or two or three different types of machines? It could be even more interesting.

That was very realistic! 20-actions long sequences blew my mind.