Good start! I tried your game and I am a fan of hard games. And I make hard games as well I finished the first level and I have one tip for you. I know you want the game to be hard and I agree and it can be hard from the beginning.
But for example the spinning platform on level one. That one feels more like a glitch when you finally make it more than you got better at the game. And the bouncing enemies are totally random and no matter how skilled you are those will kill you no matter what if you're unlucky which you'll be often
So this makes it impossible to get good at the game and I believe that it takes away much of the entertainment. Now you only feel lucky when you beat a level. So my advice is to make it really hard without using random elements and obstacles that are so hard that you almost have to break the game to beat them.
But this is only my opinion and I'm not saying that this is the correct way to do it. But I believe it would make your game more enjoyable.
Anyway, the game is still fun and addicting. You got me playing 20min dedicated to beat level one even though I didn't have much free time on my hands.
So keep up the good work!