agreed, one of the first things i thought about chapter 9 was "this feels more like every room is a puzzle"
but i also agree with the last segment scaling the difficulty down, and i actually think this is a brilliant design decision - after working your way through some of the toughest rooms in the game, you are given the reward of one final stretch where you get to fly through everything and feel great doing it. in fact, the final room is sort of designed in the same way - the beginning section is hard, but once you get to the vertical part it eases up, and you likely won't die more than a couple of times in the final segment