Listen. It's brutal. And a SLOG due to them dragging out the levels way too much, especially the final world (iykyk). I had to try some of the bosses multiple times and I was only on normal. Maybe I just suck at card games, but it felt like some of the aspects of the game were not explained very well at all.
That being said, I'm glad I played it to know what happened between 1 & 2, but I wouldn't blame anyone for just watching the cutscenes. The whole game was worth it though simply for namine's theme. One of the most beautiful pieces of music I've ever heard.