Celeste is really forgiving and doesn't waste your time though, the movement control/options are also very good. You respawn nearly instantly on the same screen and can retry each screen infinite number of times.
Certain b-side and c-side screens are really annoying though. I wish the player was given an option to skip a screen after already beating a level.
But my main gripe with Celeste is that only the first level offers a lot of freedom in how you traverse it, especially after learning advanced techniques / movement combos. That level feels kinda like in metroid games where the world gets transformed simply by player acquiring new abilities. In this case everything is already available from the beginning, but those techniques get revealed to you only in certain bonus levels.
Outside of that 1st main level you're generally far more limited in how to complete a screen. You can go faster, but most of the time you'll be using roughly the same path as on your initial playthrough simply because platforms/walls are limited to bare minimum, plus those levels start relying more on elements specific to that level (bubbles, clouds, etc.) that mechanically limit you even further. This is already approaching those fan-made levels which are usually made with the single exact execution in mind.
For a single playthrough the game is great though. Most games waste your time far more than Celeste.