Hey Le Jo, thanks a lot for the feedbacks :)
This is an early prototype and we didn't have time to add sound design but we will surely do that.
Adding a slower learning curve is indeed a good idea, and maybe introduce some features later on. We will need to think about it depending on how we serve the content.
You didn't die because you have a "bubble" that can absorb shocks 1 time, it recharges at every checkpoint. There should be a screenshake when you die, but maybe we introduced a bug. The web version runs smoothly on some configurations, but a few people had issues with it, that is why we added a windows build. On my browsers from 3 different devices, it runs at 60 FPS. Some people even managed to play on old iPads so my guess is the issue must depend on your browser and / or graphic card.