I understand that only having 24 hours to work with is a heavily limiting factor, but this was still quite a lackluster experience.
Instead of having the game be a series of levels, you probably could've made this be one of those games with infinite spawning enemies you have to dodge. Have a small grace period at the beginning to familiarize the player with the unusual movement system, then ramp up the spawn rate over time.
Plus, by having the game be one level instead of several ones you proceed through by taking damage, it makes it less obvious that getting hit is the end goal, not a mistake.
Considering that you're working with an interactive medium, the least you could do is let the player do all the cool, important bits. Instead of taking away all control for an unnecessarily long cutscene (I feel like it could've easily been half as long), have them continue to try and dodge enemies, with no bubble to protect them, expecting the worst for the inevitable next hit.
Then they do get hit, and that's when they realize that they're invincible, and the bubble was limiting them the whole time! Having the player realize this themselves helps to hammer the point home.
As a bonus, maybe during that final scene, touching some of the black hearts reveals them to also be colourful ones, representing the good friends and lifelong partners you would've missed if you stayed in your bubble and cut yourself off from the outside world.
Several paragraphs seems like a lot, but I feel like everything I said above could've easily been achieved in 24 hours.