Played >30 hours offline, and haven't even done the C-sides or DLC...yet.

Satisfying, tight controls. You know a game is headed somewhere when it's fun just to move around in an empty space. It might take a while to get used to moving in the air but that's just from my experience.
Meticulously crafted, challenging but fair level design. The game will be teaching you new techniques even after the main campaign.
Story is skippable but heartwarming nonetheless.
Respawn time is so short it'll spoil you next time you pick up a Mario game, for example.

Legendary game.
Top 5 precision-platformers of all time, I'm deadass.
If you love platformers, what the hell are you doing not playing this game.