The Nintendo DS was inordinately kind to puzzle games, adventure games, and visual novels. Its dual screen setup and touchscreen, unique amongst consoles of the time, meant that point-n-click style investigation sequences could really feel at home on a console for the first time ever, and the fact that action games were rather ill-disposed to take advantage of either opened the doors wide for developers to release those sorts of games. But it wasn't just that the platform was disposed to them: the real reason that I say the DS was inordinately kind to these games is because the DS played host to a string of some of the very best that all three genres have to offer. Amongst countless others, Capcom released Phoenix Wright and Ghost Trick, Level 5 created Professor Layton, and a company called Chunsoft (who would later be known as Spike Chunsoft) released a game by the name of 999, which would become the first game in the Zero Escape trilogy.
The story of 999 is more or less the common thriller scenario: A bunch of people are trapped together by a mysterious and sadistic masked individual and have to take part in a bizzare, sick, potentially deadly game to get out. It's less Saw and more Danganronpa: Unlike both series, however, nobody has to do anything horrible, and nobody has to die... provided that everyone follows the rules and works together. The odds of that are slim. But if you make your choices right, you just might be able to get everyone out... mostly alive.
The actual plotting of 999 is remarkably solid, and probably better than Danganronpa (although I haven't really played Danganronpa yet...): Everything connects, all the endings make sense, it also makes sense why each ending doesn't happen in the timelines where those endings don't occur. It's fairly logical, not terribly hard to follow, and while there are a few loose ends (which apparently are tied up in the sequel), I don't feel like I missed anything, or like anything terribly important just makes no sense. There are some truly astonishing twists, but they're telegraphed very well. Nothing feels unfair, nothing feels unearned. After you go through each of the endings, you'll feel like you at least get sort of an idea of who each character is, what they're about, what the history of that character is, why they were kidnapped, and how they all connect to the main story. And the story has a lovely sense of atmosphere to it: The theme of the game is wrapped in mysticism, and the whole thing plays out like a twisted, dangerous human experiment. Conspiracy, kidnapping, shady corporations, pseudoscience, people with strange and dangerous powers... it's that sort of plot. I've always loved that stuff.
I should probably specify that I'm not reviewing 999 on the DS right now. I'm specifically reviewing the version of 999 released on the PC as part of Zero Escape: The Nonary Games, which bundles 999 with its sequel, Virtue's Last Reward. There are numerous other re-releases, and there are a number of changes between them: On the PC, the final puzzle has been changed from what it was on the DS to something else. However, I'm going to very specifically recommend the PC version over other releases you can find because the PC version, unlike the original but like its sequels, provides a flowchart of all the different paths the story can take, and after you've played through a route to a bad ending, it will show you what changes you need to make to get the corresponding good ending (if there is a corresponding good end), as well as letting you jump around freely between any scenes you've already experienced. If you've ever been stuck rereading the same passages of text over and over in a visual novel, just trying to do things right this time so you'll get a better ending, and it feels like you're groping around in the dark, you'll know that this is invaluable. It also means you won't have to repeatedly solve the same puzzles.
Yes, puzzles. 999 was designed with the goal of making visual novels that could appeal to a wider audience, and writer Kotaro Uchikoshi decided to integrate puzzles. So after going through a visual novel section where you're making decisions that change what path the story advances down, you'll end up in a locked room or series of rooms and be put into a first person perspective to solve a puzzle. Essentially, it's a series of small escape-the-room games, like what you'd find on Newgrounds, but they don't require you to read the designer's mind to solve. The puzzles aren't exactly inspired, and I wouldn't say any of them are especially good, but most of them weren't particularly egregious and so long as you make sure to comb every environment for any potential clues, there's no reason why you shouldn't be able to solve every puzzle unaided... with one exception: depending on the route you take to get there, the final puzzle in the detention cells may not have been signposted properly, and as a result you might not be sure how to solve it. This is the only puzzle in the game that I think is entirely badly designed. I'll also dock points for the fact that the game makes you solve some old gems you could get out of any puzzle book: The magic square is here (verbatim), and the game also makes you solve a Sokoban puzzle. There's no twist: it's just Sokoban. So that's not... great.
On the whole, I'd say 999 is worth playing. It's not a masterpiece, but the writing is very solid, and the puzzles are good enough for me to deem the acceptable. Basically, I had fun with it.