Imawa no Kuni no Alice is the only survival game story where I can actually feel invested into many characters. Lots of times, these "death game" stories involve a large volume of people, many of them who get introduced very quickly and don't have much of a personality. They might die soon, or stay for the ride for a certain amount of time. The fact that Imawa no Kuni no Alice has a pretty large host of characters, having some of them die, and them still having unique and developed personalities with dynamic thoughts and actions is definitely a feat that I have not seen in any other survival death game. It's the only death game story with good characters all around the board. This can definitely be attributed to the fact that unlike many of the other series like these, the mysteries, the games, and the side stories all add a world building and depth of characterization that is unmatched. Everything in this story is about learning about the motivations that a character has, and what weaknesses they have. The fact that there is such a focus on this aspect of feelings the past that makes them what they are today makes for a story with rich characters.
Like I mentioned before, one of the reasons why this story is great is because of the side stories. These side stories don't involve the main cast of characters, but have a great focus on side characters. Not only are these side stories entertaining to watch in terms of death game content, it also brings along the introduction and analysis of the many different side characters that influence the plot later on. This, paired along with the large focus on the feelings of characters and the exploration of their pasts and motivation make the characters the strongest aspect I've ever seen.
Imawa no Kuni no Alice is also much more realistic in the depiction of characters' psyche. While a lot of these death game protagonists have seemingly unbreakable hearts, Alice has a lot of hesitation and darkness within his heart that gets explored in the entire series. That's to be expected. He experiences tragedy and falters, and his heart gets broken. The other characters are the same. Their life was hard as it was, so why do they have to play death games? Maybe just end it all. There's a lot of characters that don't have the courage to face death games anymore, or these death games twist their personality to an extreme.
Other than that, I think just the variety of death games that Alice plays are interesting and fun on their own right, but also the process of trying to figure out the mysteries of the island are. It was very fun seeing how the atmosphere of near death situations affects peoples' actions, and how a decision can mark the death of a person, and Imnawa no Kuni no Alice perfects this craft. Not only can the reader experience the chaos of the situation, they also in turn, are able to learn more about the characters and their inner thoughts.
Of course, the final arc was huge bust. It was pretty trashy, and it's the reason why I lowered the score from a 9 to an 8. It's a cheap bailout is what it is. Pair that along with some massive plot armor and questionable actions that some characters make in order for Alice and his friends to survive, it's definitely not a perfect novel.