Ahoyhoy. I'm so glad you like the game :) (less so that sneaky bugs appeared, but thanks for reporting them!).
Found and squashed the culprits (the first was me forgetting to add the creation location of the mirror in the Shady Wall room, the second was forgetting to remove some old code after I'd created the "Death Screen" where previously the player was only notified of death via the Text Response at the bottom, which no longer shows).
I've also added you to the Special Thanks section of the credits for helping QA test the game :)
The new version (v1.0.5) should work fine with the old saves as they aren't altered, so just install over the top of the old install. I'm using a newer version of GameMaker 2 so hopefully that doesn't cause any unseen hiccoughs...