Given all of the above, there is one design decision that left me scratching my head.
For example, in this first level, the bow is not on the critical path, even though you need it to beat the game. Why didn't the designers force you to get it? Perhaps they wanted you to revisit the dungeon later, if you forgot it? Given the extreme attention they've paid to helping the players not get lost, though, I'd doubt it.
They do this very successfully in Level 4 (which you can see in the appendix below) so I'm not sure why they decided not to do it in so many other levels.
By the time we get to A Link to the Past on the Super Nintendo, six years later, they've fixed this problem, so it's clear they weren't satisfied with it, either, but still -- I wonder what their intent was.
I want to point out how awesome it is that they were making this stuff up back then. These Masters of Game Design discovered these tricks and built on them as time went by.
How fortunate we are, to be able to look back and learn from them.
I wanted to include a few more level breakdowns, but couldn't find a good spot in the article itself. As such, I've included this appendix which breaks down Level 4 and Level 9 to show how the trends I noted earlier in the article continue throughout the game.
This level is very interesting. The flow is generally linear and ramps well, as with Level 1, but the designers stop the player in Room 6 and won't let him continue until he gets the ladder in Room 8.
As with Level 1, the designers put in a number of optional rooms. In this level, they've made it so that the optional room next to Room 2 uses the key from the room to the left of Room 1. This means that the player could potentially have to run around the level for a while if he uses the key from Room 3 in Room 2.
This isn't too much of a problem, however, since they block your forward progress in Room 6, which keeps you from getting too lost.
When I traced the critical path in this level, at first I was very overwhelmed. As with the other levels, there is a minimum amount of re-traversal required to get through this level, as the critical path is extremely linear.
One surprise was that the silver arrow is not technically on the critical path even though you can't beat the end boss (Ganon) without it. In a modern Zelda game, they would have put a gate in front of Ganon's door (and, for that matter, others throughout the level) which could only be opened when hit with a silver arrow. That way they could ensure you had to pick it up before you got there.
I've outlined the path to the silver arrow with red lines, so you can see where you'd have to go to get it. It involves re-traversing 5 rooms, which is a large departure from the norm.