This review is almost accurate. Maybe they took a little longer than expected to finish the first chapter I assume. But yes, this game isn't designed for everyone. This game is long and slow pace with little considerable gameplay. It tells a story that requires the player to think and be engaged as the story is unfolding in front of them. The decisions made need to be well thought out otherwise the arguments presented would not be able to continue, that is how those situations presented in this game worked. If I may, putting yourself in this situation, you would want to be as thorough as possible.

Again, I would like to reiterate that if you only did the tutorial (again I assume you mean chapter 1) then expect a tutorial level amount of puzzles that explain the basic mechanics.
EDIT: I decided to delete my previous comment as it has a spoiler in it that didn't need to be said.

Weell yeah, Danganronpa is completely linear. Anyways, if you want a visual novel with puzzles and decisions which change the game, you should try 999 (the nonary games). My full playthrough (or al least my ending, took me around 6 hours or so)

If Visual Novel means that the player is 100% un needed to play the game. I'd rather watch the anime. Like, there are no relevant decisions, everything you do is completely scripted, and the riddles are solveable by monkeys.

That's because it's a visual novel. This was my first visual novel ever and indeed it felt super slow, but just so you can empathize with the characters, since the whole game is about despair and hope