This is so interesting! What a great job!
I have some advice for you:
1. Change the icons on the left side and use the same block you see in the game (it is easier to understand the meaning and will become more consistent).
2. You could add a drag animation (a ghost block) because I didn't understand this mechanic at first.
3. It is strange that the action blocks also have a color (this does not help perhaps).
4. I would add an icon to help people distinguish the start and exit blocks the color sometimes is not enough (especially for those with vision problems).
Otherwise it is really a nice game, congratulations!