Good work my friend. Here are some things I could think of while playing for a bit.
The Good:
Jump upgrades were really well connected with the theme of the game.
The "Back and Forward" design to progress is good. The experience can feel like a chore sometimes due to other problems.
Good indication when there's a platform invisible to the player position. The use of the collectible was wise in this regard.
Platforms are easy to land (corners).
The parallax effect is well implemented.
Minimalistic visuals are pleasing and music is comforting.
I think the writing is good, although it could be improved at some points (played in Portuguese). But honestly, this is beyond me.
The Bad:
Platforming relies too much on perfect timing, an early section of the game is very offputting due to this behavior. Try being more forgiving and "cheating" for the player a bit, implementing a "Coyote Time" would help a lot. The video "Why Games Lie to You- The Fallacy of Fairness" by Youtuber Adam Millard - The Architect of Games has some good insights on this matter.
Auto-destructible platforms could have, at least, a minimum of visual indication. Make them tramble or slowly disappear after the player steps on them.
The part with multiples auto-destructible platforms is a bit unforgiving since you need to replay everything again, thus becoming offputting. This is not a problem with checkpoints implemented.
Collision boxes are too restrictive at corners. Make them easier to pass from below to upward. Landing should continue to be safe.
Additions:
Jumping sounds variation: just one gets really repetitive. The game music could have some variation as well.
Skip all-text button: when replaying (because of losing the game) it got a bit tiresome to see all the conversations.
I know this is a prototype, so take these ones with less urgency:
Adding more juice to the game would improve the overall experience. Search for the subject "Game Feel". The videos "Juice it or Lose it" and "The Art of Screenshake" are strong recommendations.
The use of different sprites to show character progression (not gameplay, but the thematic of letting burdens behind) can enhance the experience, I think.
Visualization of burdens can also strengthen the thematic.
