This is going to seem either beyond idiotic (which it may be) or a troll (which it is not) but: is this game actually fun? Like, if you have zero nostalgia or anything, and your evaluation of it is based solely on what it is, is it something a person in their 20s would want to play? Is it fun in a different way than, say, Dwarf Fortress is fun? (Haven't played DF but I think I understand why people do.)
Would really love informed takes on this.
"Is this fun" and "is it something a person in their 20s would want to play" are entirely different questions.
There are people who absolutely thrive doing the things NetHack rewards you for in the long term: perseverance, patience, planning, resourcefulness, risk management, strategizing, analyzing and learning systems... I feel like it has a timeless and ageless appeal to a particular kind of player and has never been quite palatable to mainstream audiences. If you like NetHack today you probably do it for the same reasons you would 30 years ago.
It's complicated. The soul of Nethack is opaque design, secrets, and emergent gameplay from mechanical interactions. In theory, the best way to play Nethack is by going in completely blind ("unspoiled"), so that you maximize the sense of discovery which is its most compelling trait. But in practice, I highly doubt that anyone in human history has ever beaten Nethack without looking up any spoilers. At some point you just get frustrated, decide enough is enough, and look up whatever spoilers are necessary to beat the game. Even getting started is rough for a beginner without spoilers, but at the same time taking a spoiler-maximalist approach is probably going to result in a pretty lackluster experience.
I'd say that, to some degree, roguelike game design has moved on, and when it comes to hilarity and sheer mechanical depth and breadth, games like Caves of Qud are probably better at evoking the feelings of Nethack without being so absolutely reliant on spoilers (which isn't to say that the game isn't still largely opaque, just that the essential parts are better-communicated). And on the flipside, anti-Nethacks like Dungeon Crawl Stone Soup make it a design goal to be fun and playable even assuming a totally spoiled player, by focusing more on tactical and strategic decisions and being forthright about including all necessary information within the game itself.
Nethack is what you get when you take a team of developers and have them focus on gameplay to the exclusion of all else. No graphics, music, marketing, apps, action sequences, or profit motive. Just pure gameplay, with a richness of interactions and possibilities unmatched by more polished modern games. Nethack is so well balanced that, for most players, being gifted the three most powerful items in the game from the start barely affects your winning chances.
AI researchers think NetHack is interesting [1, 2]. You should too!
[1] https://proceedings.mlr.press/v176/hambro22a/hambro22a.pdf
[2] https://arxiv.org/abs/2403.00690