Hi! Thanks for taking the time to play and think about the game :) You are completely right that the illusion breaks quite easily (we had some people just click enter to get through everything instead of even pasting echo like you did!)
Not being able to parse input more robustly is my biggest regret about this game, and we're working on a version with real branches that responds to your input (we're making it in ink and everything!).
Mostly you're right about all of that being because we had a strict time constraint, and to save development time. The rest of this isn't meant as a defense, but if you're interested I'd like to tell you about a bit of the philosophy behind the game, and (at least speaking for just me) where our heads were at when we made it.
We made this game pretty soon after I finished Zenosyne, which is a journaling game where the game asks you questions and you answer them. The game doesn't do any checking of player's responses, just reflects them back at you. I was impressed by peoples' ability to project meaning onto the game, and I was wondering if I could use the system again. Would players self-check themselves? The answer from out of ctrl seems to be a resounding sometimes and when players push against the bounds, they find a broken mess, the magical illusion broken.
The other facet is that we like visual novels! I wonder if you would have had the same feelings about the game had we listed it under visual novel instead of interactive fiction? Perhaps interactive fiction carries with it too much expectation about multiple endings.
Particularly I've been really inspired by this idea of "multiple middles" espoused by die gute fabrik http://gutefabrik.com/craft-multiple-middles/ in mutazione. That the player could make meaning for themselves in the middle of a story is super interesting to me. Are you actually changing the story here when you type different things? I'd argue that since you're changing what echo does, you are changing it somewhat, like if you could determine the dialogue for just one character in a movie. Maybe that's just not a satisfying way to interact with a story.
Anyways sorry this ended up long, I love talking about games and I guess I got long-winded about it :P Thanks for playing!