Room numbers

[Norbert]

Princess level.

[Norbert]

Potions level.

[David]

For instance, what he saw as the core of each level and what were afterthoughts.
For some levels it's clearer than others.

Well, on level 3 room 1 is the skeleton, on level 6 it's the shadow, and on level 13 it's Jaffar.
However, level 4, 5, 8, or 12 don't "start" from their special rooms.
On level 1, 4, 7, 8, and 10, room 1 is simply the room where the player starts.

By the way, I see you made the maps with SDLPoP.
I guess this is the easiest way to make maps with room numbers.

[Norbert]

Some unused rooms also tell a story.

The demo level, for example. If you add unused room 3 between rooms 4 and 2, you get four neighboring rooms in this order: 4, 3, 2, 1. Then, look at the raise button triggered by the prince. This is event 2 (E:2), which, from left to right, triggers all gates in rooms 4, 3 (2x) and 2. There's enough time for the prince to make the final two gates if room 3 is included, so Mechner originally planned for a longer demo. (Perhaps much longer, looking at other unused rooms.)

[atrueprincefanfrom18]

For instance, what he saw as the core of each level and what were afterthoughts.
For some levels it's clearer than others.

When I saw the room numbers for the first time, I had no idea why the rooms are arranged in such a manner and not in sequential order.

Well, on level 3 room 1 is the skeleton, on level 6 it's the shadow, and on level 13 it's Jaffar.
However, level 4, 5, 8, or 12 don't "start" from their special rooms.
On level 1, 4, 7, 8, and 10, room 1 is simply the room where the player starts.

Interesting! Nice observation.

[...] so Mechner originally planned for a longer demo. (Perhaps much longer, looking at other unused rooms.)

I am not sure how many people have seen the demo till now. I saw it after completing whole game when I was curious what happens to the cutscenes. After the last, Jaffar text, I just played enter and I thought I had seen everything of it, so never really took more interest in the cutscenes afterwards.
And then later, I found out that demo level existed. (And I even tried to play it in the DOSBox, but Level 1 started! )