You can get to the other cliff by double jumping where the bottle was. The more you hold the jump, higher you jump, if you pressed then released directly, it will do a short jump. Also, you can use the charged attack of the weapon (right click) to "boost" you. I'm sorry, I kinda knew that maybe I had to do some tutorial to introduce the double jump and the charged attack, but I ran out of time...
And I tied to do a web version, but the game stuck on the beginning when I clicked the buttons and didn't know how to fix it.