I loved this game! It may be one of my favorite games of all time. But, as a (future) designer, the thing that I loved the most is the versatility on the difficulty, as in how hard do you want the game to be.
Starting with the Difficulty Settings in the Options menu, that allows to change certain aspects like Enemy Damage, Enemy Attack Frequency and Puzzle Times, which allows this game to be as easy as you want to be in case you're not good at these games. This means accessibility for everyone, which is something many games need these days.
Then, due to its Action and precising nature, it doesn't limit you with grinding and Level Requirements. You can (almost) beat the entire game without having the required equipment or level; it warns you, but it doesn't stop you from doing it. I remember fighting like two or three bosses with under-level equipment; it was hard, but it was doable.
Great Game Design right there. Cheers!