Very fun game, really nicely done! The character abilities were great and ran smoothly. I liked how many different upgrades there were to find, and how you spaced them. The behavior and variety of the enemies/bosses was excellent. Once I had all the health and ability upgrades, I tried to double-jump, lead-suit, and brute force my way across the river, and saw a message like "Congratulations, you...without dying...", never saw it in full :).
Some hopefully helpful feedback as you develop further: I died once mid-air, and my body then fell into a gap that would transition you to a room below, and it softlocked. I also got the same crashes in web upon entering the rooms toward the beginning that have been noted by others on Windows; that guy who walked away in there made me so curious, too.
Awesome work!