Hi Adventuron! Thanks for your input.
I was aware of many of these issues, but simply ran out of time to implement solutions. I know that you've said elsewhere that people could keep working on their entries after the deadline, but that felt a bit unfair to me. Still, since you're explicitly advocating it to me here, I'll work on the game some more today. I want to make a few responding comments though.
1. "READ SIGN" etc.
Yes, I completely agree. Unfortunately, in order to save time I just crossed my fingers and hoped that players would EXAMINE everything. Also, I didn't know how to define aliases, and didn't have time to write a bunch of extra "match" statements. It seemed unusual for a text adventure system not to support aliases, but it wasn't mentioned in any of the documentation that I was able to find. Now that I know, this will be a quick fix. Is there a comprehensive reference document somewhere that I've missed? I've found some more since the deadline, but still no full manual.
2. Manipulating the valve.
The majority of the inputs that you listed are actually recognized by my program; the response "Why should I do that?" is specific to that puzzle, and not a canned response. Shutting off the valve is part of a longer chain of puzzles, but neither the game logic nor the story make sense if you shut off the valve before performing some other actions. I managed to do some rough playtesting with a couple of friends last night, and they both made similar complaints. I've thought of a better way to block this action until it's appropriate, and I'll implement it today.
3. Non-vital inputs.
There is plenty of room for improvement in this regard! I hardly covered any of these at all.
4. Customers at BurgerCorp.
Yes, that's a good suggestion. I'll add a message on entry to the location.
5. Applying for a job.
More non-vital/guiding input.
Thanks for all of your suggestions!