I loved The Divide, so I decided to check out this one too. It's just as good, though maybe a bit too spooky for me. I could also use a hint with this game -- your puzzles are so complex!. I have two pieces of rope, and I know I need a third one to get across the ravine. I also opened the cellar, but not the chest in the right room. At this point, I'm kind of stuck. Could you give me a hint?
Sounds like you're actually almost there. There's one rope in the cliffs, one in the cave, and one in the cellar. It sounds like you need the one in the cellar, but that means that you beat the two headed monster without rebar, which is impressive (that fight is quite a bit easier with rebar).
The chest you haven't opened has a key that lets you unlock a safe in the cellar, which has the rope and rebar inside. You can find a hint to the chest combination upstairs which shows a similar but different puzzle with the solution. If you can figure out how the solution works, you can then use the same method on the chest. Otherwise, try googling "japanese visual multiplication" and you'll see the method I used.
Let me know if you're stuck on something else.