This is so good, enjoyed it a lot! Coming in, I expected it to be a precision platformer, but turned out it's a puzzle platformer with a really well-thought mechanic and theme! I really love the ending. Noticed the skull in the beginning and I was like "why is that thing there?"
And when we reached the monster, I am like "oh is that past and future?" and I thought it was just going to be appearing there but then the ending hits me. Well done. Great foreshadowing, great storytelling, great puzzle. Love the arts.