Its just side thing for couple collectibles and not needed to progress. None of the parkour in the game is not needed to beat the levels. Its intentionally challenging, but its not frustrating to those who have played lot of 3d platforming from what i've gathered. If you want some tips: player has air control, you can move while in air, meaning if you think you're gonna overshoot a jump, you can slow down in the air by holding "s" key. Holding "shift" at the same time will make you slow down even more.