Thanks for the feedback!
In most Metroidvania games, the jump height depends on how long you hold the jump button. My game works the same way, but I didn't mention it in the tooltips because I thought it would be obvious. That was my mistake—sorry about that.
As for the CRT filter, I agree it's pretty strong. You can turn it off in the settings if you prefer. That way you'll get to enjoy the pixel art in full high-definition without the filter.
I hope you give it another try! There's a lot more fun stuff to discover as you progress. 🙂