999: Nine Hours, Nine Persons, Nine Doors
"999: Nine Hours, Nine Persons, Nine Doors" for the DS is a masterpiece of a game. It's a visual novel which usually isn't my cup of tea, but with this being a cult classic game that I've had on my radar for literal years, I figured it was time to play it. I went into the game, and the series completely blind, and while I did use a walkthrough because there are 6 different endings, you should definitely play it as blind as possible.
"999: Nine Hours, Nine Persons, Nine Doors" is an escape room game where the participants are put into a life or death situation. Your goal is to escape while keeping everyone alive. While there are plenty of branching paths, there's only one true ending. Despite this, you'll want to explore as much as possible. You'll learn much more about each character, why you're there, and the overall story of the world you're in. After checking the reviews for the steam port, the one that stood out to me the most was the one that said "permanently altered my brain chemistry (positive)", and I think that's probably the most accurate description.
This game has two sequels as well! The series is referred to as the "Zero Escape" games. "999: Nine Hours, Nine Persons, Nine Doors" is apart of "The Nonary Games" and has a direct sequel called "Zero Escape: Virtue's Last Reward". And "Zero Time Dilemma" is the final game in the series and while still has some pretty high praise, the reviews for it are bit more mixed.
Spoilers
While the Steam port of this game is excellent, and has some great quality of life features, the DS game has one advantage in that the final puzzle was made for the DS.
I genuinely said out-loud "Oh man, that's really neat" when I encountered it.
There's a review on Steam that spoils the final puzzle, and it says "Most emotional sudoku of my life" which again, is a very accurate description.
One of the bad things about this game being a cult classic is that it's very expensive on DS. Luckily there is a PC port that does add a bunch of quality of life changes, Japanese and English audio, and better graphics. I definitely prefer the DS port despite some shortcomings because of one puzzle, but if you don't have access to that, the PC version is excellent.
Check out my thoughts on Zero Escape: Virtue's Last Reward and Zero Time Dilemma.