This is obviously a subjective question, but I'll give you my personal opinion. Little Nightmares II does a lot of cool new things. It gives you the ability to use melee attacks; it offers more complex puzzles more open areas. It also has better visuals, and in terms of horror, I personally feel that Little Nightmares 2 steps things up, with the Mannequin area being a super spooky highlight. However, I still feel like Little Nightmares is a much more charming and complete adventure, and in terms of revolutionizing the genre, the first game did so much, whereas the sequel just feels like more of the same. Both are great games, but the first is my favorite of the two.