Interesting. I also found bugs and errors.
Am I able to reset the canvass somehow? Also when I start the game, I'm not able to see all buttons without expanding to full screen. I suggest you to make enlarged "arrow"-nodes, so the dragging is much easier. There shall (maybe) be a count for each of program items to use, and i would like to be able to see the "start" and "end"-blocks at the start, because they are on limited each other.
This would be nice themed with space theme, where you're programming a space rover loaded on some gems. Then you would add 2 or more rovers that uses same/or different control mechanics from the list.
Still good concept here though and would be playable on the mobile devices as well. This is mostly expandable concept, and it is very nice!
Edit: Glad you had shared this till, though. As we can see you almost run out of the exporting time.