First, the good news: The only reason I clicked on your game was because of the neat art style. You clearly have some artistic vision and skills to put them in practice. The menu design is fabulous, the level (as far as I got) was also super atmospheric, and the music complements is very well! Good job on that!
Now, the setback: I tried, ok? I tried and tried, until I figured out what's wrong with the mechanics. Your character gets enough speed, but doesn't get enough HEIGHT when JUMPING. I added a drawing to explain what's wrong. You simply don't have enough vertical interval to make every jump succesful. Luckily the character sticks to the geometry, and you can double jump from the corner of a platform, but most of the times, with these narrow settings, it's too darn impossible and gets really frustrating after 50+ tries, even though I wish to see the rest of the game. Did you test it enough? Give your game to 30 people to play and give feedback? When building a level, every object needs to be calibrated in the perfect distance (and with a larger interval for the margin of error, yours is too narrow interval, like in my drawing below).
P.S. I did not rate it yet, because I think you could add more height to that jump. In fact, I really wish you update it, so I can finish this amazing little game!! :D Play test, play test, and more play test!!!
I'll be checking in every day to see that you fixed that jump height ;) Cheers!