That's true of games like Celeste. But this game is supposed to combine elements of Celeste and platforming games with the frustration of games like Getting Over It and Jump King. The design goal is for the player to overcome debilitating setbacks and failures. In a way, losing progress is the game.
Your quote is gold though. I've tweaked the physics slightly in the new version to remove the "slipperiness" of the character, because the platforming is still almost as hard and I want the player to blame themselves and not the game. Be on the lookout for the next version in a few days.