Just everything, honestly.

The battle system for starters is constantly asking you to think smart. You’ve a gauge that you have to keep centered to be “in the flow” such that you can’t blindly use the best attack every time. You always start every battle with full health and mana - so you never have to ration between fights. Which adds up that every fight can be difficult. There is no cannon fodder.

You level up as the story progresses so you can’t simply grind to a higher level. There is a level system but it’s more a skill mastery one It respects your time in that you will never need to grind for anything.

The puzzles are difficult enough to be challenging but not so much that you will ever need a strategy guide.

The story is relatable without being convoluted.

The world makes sense and has no suspension or disbelief moments. Speaking of it’s a world in which both Dragons and Giant frickin robots are both natural, and they make sense.