It was a bit hard to grasp at first, but the help and hint commands got me on my way. The puzzles were quite enjoyable, but the fail state was a bit too over the top for my liking.
Also, 5_userspace actually has multiple solutions. You can let one go up and then close d1, resulting in the other go to the left. Alternatively, you can close d1 so that both go to the left, one will get killed and the other will come back again and go to the right. Perhaps the others have too, but this one stood out to me.
In level 7 it is okay for the core at d1 to get killed as long as the one at d3 survives, but the same doesn't apply vice versa. I found this kinda odd. After this level it said the new computer was: '[blank]'. Where there more than seven levels?