Spoiler-free review. This is simply a general opinion about the game without touching on important details.

The Blind Forest had an incredible level design, soundtrack, puzzles, cinematics, frenetic boss chases and platforming. But Will of the Wisps ramps it up to a level I thought I found already hard to beat, the game definitely exceeded all my expectations and ticks the boxes where I felt there was a margin to improve upon things felt out of place or a bit janky in The Blind Forest (For example, I'm happy that the Spirit Flame skill was replaced for Spirit Edge, in The Blind Forest, it felt like Spirit Flame was doing the combat for you, where as in here Ori is actually fighting the enemies under your control).

In Will of the Wisps, all levels have their own art style with vibrant colors, effects and breathtaking music, simply everything come up together beautifuly and there is very little to complain in here.
The only thing I didn't quite like in this game was the amount of backtracking if your focus is to simply beat the game. However, there is an incentive to backtrack and explore new areas because as you progress and unlock new skills, you'll be able to reach zones you thought to be unreachable at first, which allows you to unlock more secondary missions that expand the story a bit more, sometimes these missions open up more parts of the map.

The endgame felt challenging and rewarding, that's all I can say to avoid spoilers. All in all, I highly recommend buying the game, full price or not it's well worth your time.