We are constantly keeping an eye on the difficulty and challenge of the levels in the game.
We admit - it's a tricky balance! Too easy and you'll get bored; too hard and it just feels daunting and frustrating.
That said, we always welcome feedback on specific worlds, levels or bosses that you find unfair or frustrating. Feel free to submit a request; the more specific you can be, the more actionable feedback it will be for our designers.