Ori 2 is nearly a flawless game to me. It's strongly arguable that it's the best looking 2D game of all time, every movement mechanic it introduces is like The Best Movement Mechanic, it has cinematic scripted chase sequences but also strong pattern recognition bosses, punchy combat feedback, tons of different areas that each have interesting gimmicks, fluid pacing the whole way through, a great OST, and while I don't cry my eyes out at the story, the emotional core is beyond solid for this type of game and leads to a satisfying narrative climax and ending. If I had to nitpick I'd say the enemy variety could be a smidge better but we're really splitting hairs here. Even if it isn't my favorite, objectively speaking it's hard for me to name any sidescroller that's a better overall package when it comes to sheer ideas, execution and production values.
Hollow Knight is a game with phenomenal highs but also some glaring lows. Starting with the good, it has by far the best atmosphere I've ever experienced in a sidescroller. Namely, Deepnest is a complete triumph of aesthetics and game design colliding to make for an unforgettable S-tier experienece. HK also excels as a combat-focused action game with extremely tight controls, satisfying hit feedback, and a veritable treasure trove of challenging enemies and bosses to conquer. As a Metroidvania, though...idk. I'm pretty smitten with its world design at a macro level with how the different areas sprawl out, loop back, interconnect, and are accessed. At a micro level, HK cribs a bit too much from the Igavania style of level design for my liking where it feels like every other room is not too interesting, or worse, A Really Long Hallway (on top of most areas feeling at least a little bloated). Unlike games like Ori and Metroid, the movement abilities are none too interesting here and do little to make backtracking feel as snappy and fun as they should. Pacing is also a little sketchy with the lack of easy fast travel (paired with said elongated map design) asking for a lot of your time simply moving between places you've already been, and the ability pacing is absolutely fucking dire. Now I don't need every Metroidvania to be paced like Super Metroid where the game is machinegunning new abilities at you with reckless abandon (even though it stimulates my X Spot mmm yesss), but there has to be a better balance here. The ability rollout of HK is so fucking glacial that it keeps me up at night, and again the vast majority of abilities are as basic as they can be with double jumps, dashes etc.
It's possible that HK has higher highs than Ori with its more elaborate boss fights and Deepnest, but as an overall package it's Ori 2 for me pretty easily. That said, I'm very excited for Silksong to see how Hornet's increased agility over the Knight can increase the flow of gameplay (sprinting wooooo), and hopefully the pacing is stronger.