Bug/Glitch Alert (hope I can explain this properly): I downloaded the latest version for Windows. I started with the pre-existing save files (the one before Chapter 4). Whenever I go to the temple with the Rotten Grove (before and after obtaining the golden key), I couldn't enter any of the locked rooms. I can go nearly anywhere else in the temple; the pool, the gardens, the underground maze, and the treasure/trap room. The only other room I couldn't enter was the boss room of the temple, but I'm not sure if that room closes after the mission in the area.
I also couldn't find any of the small keys in the area. I couldn't find it in the pool, the (non-toxic) garden, or the 1st room with the piano where I was supposed to get the key. I manage almost every other room in the game by repeating the steps to get them open normally, except for the ones in the Rotten Grove's Temple.