I'm going to try it again for sure, I want to see all the writing!
I thought about it a little more and the only design thing I'd say is to maybe let the player experiment a little more off rails. Sometimes it makes sense to block the player from doing one thing before another thing, but sometimes it doesn't (like having to try one item and then use the other so the in game character catches up to the real life player thoughts, it's nice to have them more in sync). It's better to block the ability to get the needed item entirely than say that they're wrong for using the item on the thing when they aren't. For instance, once I figured out the pattern it would have been nice (and I likely wouldn't have gotten stuck) if I would have been able to try something crazy and it just works (maybe have the character be surprised by it working).
It also has to do with the normal flow for adventure games and what people are expecting, for instance if your game requires trying Item A on Thing 1 and then trying Item B on Thing 1 it can make people stuck if they've already tried Item B on Thing 1 (why would it change). While it may totally make sense in your game, people may just never try Item B again because in most games it wouldn't change the outcome. It feels a little crazy and desperate to try something you've already tried and been told no. Technically your game is more clever than a lot of other adventure games, but because of the context it ends up being confusing.
I'm only giving this much feedback BECAUSE I think it's already great! Also, if you want to delve deeper into giving clear instructions/feedback, I'd highly recommend Don't Shoot The Dog, which is a book from an entirely different domain - animal training and operant conditioning - but I think a lot of the lessons can really apply to game design.