Interesting and meta concept but it doesn't work great in execution. Spoilers follow.
btw I wrote a walkthrough: https://pastebin.com/raw/BrEQNeaA
For one, the ability to edit nearly everything kind of renders the whole game meaningless. After all, I could just edit the starting room's description to look like it says "you win", but doing so feels empty. In a way, editing a golden apple into the room feels like a hollow victory, but not to the same extent.
On the flip side, the editor is not open *enough*. The game has special items and rooms that aren't listed, even though the listing is supposed to show "everything" in the codebase. I'm talking about the mug and anomaly mug, and the ending room you get to after drinking from the mug. None of these things are listed. Not only that, but I don't see a way to modify the behavior of world items, what item IDs they will accept with the use command to affect change, or even how to give a room multiple "states" that it can switch to when key items are used. For example, how exactly does the starting room automatically kick you into the courtyard when you use the wet blanket on the bars? I see no such data represented in the window world item, the cell room, nor the wet blanket item. This is special hard-coded behavior that can't be implemented with the data structures and commands the game provides. If the cmd command was truly open, the player should theoretically be able to remake the base game, type help, from a blank canvas. But this does not seem possible with the tools the player is given, and honestly, I question whether the two included web games were actually submitted by players or if it's just an easter egg.
Edit: as I say this, I notice an 'actions' data structure that I didn't notice before.
So I retract quite a bit of what I said, but this actually raises new problems. The missing items and rooms are still a problem. Anomaly mug has item id 9, but trying to view the item results in the editor saying there is no such item. This is either hard-coded behavior that was overlooked or a major design flaw in the editor itself. You shouldn't be able to lock yourself out of the game's data structures like that. This is like if you had a codebase, and your text editor allowed you to "hide" a function, and in doing so, the function is completely inaccessible from said editor. It's in the file, but you can't see it. You can't unhide it, because to do so would require you to be able to view it, which you can't, because it's hidden. Would you use a text editor or IDE that does that? I sure as hell wouldn't.
I really think that the hidden attribute should be removed entirely. I get that the engine is itself part of the game, but when you can link the start room directly to the end room, I see no reason to even have a way to hide things, and as I discussed above, this only causes problems from the editing side of things.
So if I have JUST ONE takeaway for Nick: remove the hidden attribute from all of the data structures. Its very presence undermines the editor.
Also, from reading other reviews and the responses to them, it seems the `cmd save` command is supposed to save your progress. If that's so, then it's bugged, because it didn't do that for me. It saved the game's *data structures*, so any edits I made to item descriptions, or item/room bindings were still there, but when I loaded it afterwards, it reset me to the beginning of the game. It did not save my progress. Guess I just misunderstood
Edit 2: I saw what Bom said about the reason for hiding some of the structures in the base game, and I raise a counter suggestion: how about a 'warn' attribute that causes the game to warn you if you try to edit something that the dev believes will ruin the fun? This will satisfy the player side by warding them away from something while not completely locking down the data for the editor side.
In any case, thanks for reading my feedback :)
Re (edit 3): sure! I'm working on another speedrun right now to see if I can break into room 5 from the cell window, but I'm running into trouble because the game won't let me use the pot on the window or say a magic word to activate the action. So far the best I have is...well, I'll put it in the pastebin as "even faster speedrun walkthrough"
edit 4: Nick and I had a chat and he's got some improvements coming along. Notably the base game is no longer locked down. You can use `cmd spoilers show` to reveal any objects that are hidden. There are some other improvements in the works, but bear with him. AS2 is a very crusty dinosaur of an ECMA language and frankly it's amazing he got this working at all.
edit 5: I made my own game. cmd web play 3. It has four endings ;)