Ran into a similar bug in the same dungeon, posted this on the forked Github page:
Game: Legend of Zelda: Link's Awakening DX HD
Version: Latest (1.0.0)
Area: Turtle Rock (Level 8)
Issue: Used all keys prior to small key lock shown in second screenshot leading to underground route that leads to boxing miniboss. Specifically, attempted to open door shown in first screenshot. Cannot progress further in dungeon and game as a result.
How I ran into this issue: I solved the floor tile puzzle, used the arrow on the secret eye statue, defeated the bomb-eating miniboss, the Crusher miniboss, the mummies and the flying bat enemy to get their respective keys. I attempted to open the door seen in the first screenshot from the side seen in the second screenshot twice. However, the door would not open despite the key use sound effect playing. Furthermore, I checked my inventory and the keys were no longer listed. I used the remaining keys I found to get up to the small key lock seen in the second screenshot, but I don't have any more keys to open the lock. Thus I can't progress further in the dungeon and the game as a result.
I know this game got DMCA'd, but if anyone has a solution to this, or knows how I can edit the savegame0 file to regenerate at least one key I need to open this lock, please let me know as I'd hate to give up on this game solely due to a softlock glitch like this.
