One-shot strategy games?

Searching for games that fit, I am reminded that there's a frustrating number of games that have a difficult mode, but refuse to let you play it until you've beaten the game on an easier setting (sometimes more than once!)  It might be possible to work around that by copying someone's save file.

This list isn't super filtered, but here's some games that seem vaguely in line with your request:

Solar Settlers
Short strategy game with somewhat-risky exploration, pointed resource optimization, and exponential growth (if you play well).  Advertises a 10-minute playtime, but I think (this was years ago) that my games lasted more like 1-2 hours; I expect this is partly because I'm slow but partly because the better you play the more stuff you need to manage.

I think (66% confidence) the difference between difficulty levels is just how many points you need to count as a "win", and that you can finish the game even if you reach that threshold, so you could maybe tune the difficulty of the exercise by asking for a different score than what the game says.  (Though IIRC there's a regular play mode, and a skill-calibration mode, and I think only one of those lets you keep playing after you reach the target score, and I don't remember which.)

Defense of the Oasis
Explore the map and invest your followers into exploiting various terrain features to prepare for a barbarian invasion.  Short levels escalate in difficulty, play until you die.  Starts easy, but you could probably pick some number of stages (or some score threshold) that would be challenging.

Various Roguelike Deckbuilders
Those I've played tend to be a bit longer than you asked for but not hugely so.  The default difficulty is often hard for players unfamiliar with these types of games (but easy for veterans), and there's often harder unlockable difficulties.  There's typically "rules-based" hidden information in the form of not knowing the full set of cards and challenges that exist in the game, but rarely any "gamestate-based" hidden information.

The best-known is Slay the Spire.  I think the original and the hardest I've played is Dream Quest, but it's very luck-dependent.  Some others that have informed my impressions of this subgenre include Monster Train and Roguebook.  There's a zillion other ones nowadays.

You mentioned Luck be a Landlord, which is sort of on the edge of this category; compared to most I've played, it's faster, simpler and has no hand management.  Another game I've played that's on the edge of this category is Crop Rotation, which is more of a tableau-builder than a deckbuilder since all your cards are available at once (there's still luck, but mostly in what cards are offered in drafts).

Into the Breach
A tactical battle game where the enemies need to charge up their attacks and you can make them miss (or even hit each other) by moving things around, and you gradually upgrade over a series of short missions.  I think this one actually lets you play on hard mode from the start, but I don't remember for sure.  Not much in the way of hidden info.

You can vary the game length by choosing to play 2, 3, or 4 islands before doing the finale.

ETA:  Tyrant's Blessing has very similar gameplay and is much less likely to have already been played by your audience (though it's so similar that I'd expect a lot of skill transfer, and I'm uncertain about the difficulty and playtime).

Renowned Explorers: International Society
This is likely too long, but allegedly there are players who can finish a run in under 2 hours.  It's basically a combination of story events and turn-based tactical battles, with periodic breaks to spend your accumulated resources on upgrades.  There's a mechanic where you can do extra events for more resources at the cost of taking penalties that make the fights more difficult.

It's not that hard, but if you restrict yourself to only choosing expeditions from the highest-unlocked difficulty rating then most players probably won't win their first run.  Experience at tactical skirmish games may provide a significant advantage.

ETA:  Thought of a couple more, although these seem even less promising to me:

Farm Keeper
Turn-based economic strategy where you need to make escalating rent payments.  The starting difficulty is almost certainly too low for you, and once again, it only unlocks higher difficulties one at a time as you win.  Meeting various conditions while playing also permanently unlocks "secret tiles" that make all future runs easier by giving you more (and typically better) options.  Harder modes are also longer and may exceed the playtime you want.  So setting up an appropriate challenge might be painful.

It's also somewhat unfair as a one-shot exercise, because as you play you get access to new tiles that substantially alter the optimal layout, but you can't move your existing tiles and you can't see the late-game tiles in advance, so you can end up getting punished for having done a good job of optimizing the variables that you knew about.  (Though conceivably this teaches something about flexibility?)

Lueur and the Dim Settlers
This game actually isn't even out yet, but there's a free demo.  The demo is certainly too easy for your purposes.  But it's a relatively short turn-based survival strategy game where exploration plays an important role.  (Note: I have only a vague memory of how long this took to play.)

I think there were some simple action-based mini-games, too, so it's not pure strategy.

ETA Again:  If unknown information is not such a priority, one could also look at some solo-friendly strategy board games--several of which have digital versions, such as Spirit Island, Aeon's End, or One Deck Dungeon.

I see a lot of roguelites in the comments (many of which I will happily second, particularly Slay the Spire) but my vote and highest recommendation go to the traditional roguelike Brogue.

This game got me into the genre, so I do have a bit of a nostalgia bias towards it, but it is heavily recommended in traditional roguelike communities and considered to be a staple.

Brogue is as traditional as it comes -- descend into the procedurally-generated dungeon, pick up the Amulet of Yendor, and escape with your singular and fragile life. In my view, it is a refinement and distillation of this formula and of traditional roguelike strategy mechanics into something endlessly replayable and perfectly streamlined.

I would say it meets both your first and second qualifications. There are milestones, both with each floor of the dungeon, and ones that are typically community-defined, and a run in two hours is feasible. However, it is incredibly difficult to win on your first try. I have never heard of anyone doing it, although I'm sure that they have. Among myself and my IRL friends who I have gotten into it, I am the only one to have successfully beaten it, though two of the four of them have gotten very close multiple times. There are players capable of winstreaking it in the community, even when taking on optional additional objectives and descending even deeper into the dungeon than necessary. Every seed, random though it is, is fundamentally winnable and fair. Unlike in many, many similar games, I have never once walked away from a death thinking "that was bullshit" -- there's something beautiful about that, to me. It feels like an elegant game of something almost chesslike, purely my own strategic merit and improvement run to run against the computer.

Regarding strategy/resource management/hidden information/value of information:

• Strategy: Every single turn is a strategic decision of some form. Your hunger ticks away, slowly but surely, pressing you deeper into the dungeon for food. Monsters that could overwhelm you in an open space can be safely handled in corridors, and vice versa. The environment itself is a strategic consideration -- burning a bridge an enemy is crossing may save you now, but you've kicked the problem down the road, making the next floor more dangerous. Setting the grass a group of enemies is patrolling aflame could damage them and force them to reposition, but be mindful of the fire's spread. Steam, or cutting off your escape route, could both prove deadly mistakes. Additionally, each weapon type, armor, scroll, and magical item is unique, with its own benefits and drawbacks. There are vaults full of items, of which you can choose only one to bring with you. You must make the best choices with what you find, which ties into resource management.
• Resource Management/Hidden Information/Value of Information: This is a key aspect of Brogue. Your consumable items are limited, and there's a hidden information trick: all items start out unidentified. Potions are known by color (random from game to game) and scrolls by strings of gibberish. Magic rings, possibly beneficial or cursed, are known by their material, as are wands and staves. You can tell that a spear is a spear, but is it magic? Keenly edged, or perhaps with a rarer and more special enchantment still? Or is it cursed? There are scrolls and potions capable of detecting magic and identifying items. In a pressing situation, where your current gear may not be up to snuff, do you take the risk of equipping something unidentified, or seek another solution? The game provides you with percentages for each unidentified item, so you can make semi-educated guesses, but the art of managing your hidden information is a game within a game all by itself.

Last but not least, a few technical details: The game is free. The community edition is still continuously developed and updated. It runs on Windows, Mac, and Linux, and the entire app is only a couple of megabytes.

If anyone tries it out, please let me know what you think and how you like it.

I think your list of conditions is very restrictive; to the point at which it's really difficult to find something matching it.
Most (all?) modern difficult strategy games rely on some version of "game knowledge" as part of it's difficulty, expecting you to experiment with different approaches to find out what works best -- this is a core part of the game loop, something specifically designed into the game to make it more fun. This is baked into the design on a fundamental level and is extremely difficult to separate out.
Combine that with the one-shot nature and a strict time limit (so strict that in a large amount of cases this isn't even enough to start making meaningful strategic decisions: either because learning all the systems takes longer or because you need to progress through the game enough to be aware of the later payoffs) and you are basically rolling a die on whenever you can land on a solution or not via some combination of prior gaming knowledge and luck -- I don't think you can meaningfully "try harder" to guess the decisions the game designers have made about the systems and obstacles you've not seen yet (besides playing more games beforehand of course, collecting game design principles trivia along the way).
Yes, you can bias the roll in your favor with genre savviness and experience; one of my friends has an absolutely uncanny ability of picking excellent builds in games with no prior information. He has also played games for some inordinate amount of time in order to build this intuition up.
 

Tentative recommendation of Slipways; the VOI part isn't as central as I suspect you'd like, but sending out probes sure does cost time and money you could use for settling planets and forming trade routes; and while it's easy enough to survive to the end of your term, it gives what you're asking for if you choose to define 'victory' as 'get 5+ stars on Tough'.

DCSS?

Lots of people have mentioned various flavors of roguelikes. One of my goals is to have games in different genres. I agree that roguelikes are often a good source of the qualities I'm looking for here but part of the point is to try applying the same skills on radically different setups.

Another thing I'm interested in is "ease of setup", where you can download the game, open it up, and immediately be in the experience instead of having to do a bunch of steps to get there.

Stratego

It's old and not 'fancy', but it contains all the required elements. Balancing explore/exploit, hidden information, strategic risk-taking, difficulty that can be tuned to be subjectively high but still beatable (against an adjustable computer opponent), a single game doesn't necessarily take very long (and can be explicitly limited by turn-time-limits).

https://deepmind.google/discover/blog/mastering-stratego-the-classic-game-of-imperfect-information/

Disrecommending Slay The Spire. While it's a great game and it fits the rest of your criteria like a glove, it has very little hidden information in a practical sense (one of the more innovative things about it is that you can almost always see what the enemy will do next turn), and as such has basically no places where explore/exploit tradeoffs and VOI calculations would be relevant (I assume that this isn't a negotiable part of what you're asking for; if not, yeah I also recommend StS).

If you choose a single player game, you are going to have to carefully calibrate the level of difficulty and the type of difficulty. However, if you pick any two player comptetitive strategy game you can focus on the type of difficulty, as the level of difficulty will be calibrated automatically to "half your participants will win."

My recommendation would be to rig up a way to randomly sample from the two player board games on boardgamearena.com that neither player has every played before (can be as simple as putting 20 names on index cards, the players remove any cards they recognize, then shuffle and draw).

Engine game? "Deckbuilding puzzle game with daily challenges."

Several thoughts occur, in relation to this list of criteria.

• Is 30-120 minutes supposed to be how long the game would take if you were playing normally, or if "you were taking a long time to think each turn or pausing a lot"?  I'm a pretty thoughtful and methodical player in strategy games, and some genres of game seem to take me as much as 2-5x as long to play as they take for a typical player, so this can make quite a difference.  (Though the upper end of that range may only apply if I'm actually pausing to take notes.)
• Are you looking for games where a typical player on their first play will lose, or where they will take longer to win than the given timeframe, or is either fine?
• With respect to "value of information", I usually make a distinction between learning gamestate and learning rules--for instance, in Poker, the first would be learning what cards someone has, while the second would be learning whether or not a straight beats a flush.
  • Hidden gamestate generally has precise bounds for what it could be (if you already know the rules), but are generally made deliberately unguessable within those bounds.  The rules of the game have no strict boundaries on what they could be, but usually aren't designed to be mysterious, and your ability to guess them may be extremely dependent on how much experience you have with similar games.
  • It would be extremely unusual for a game to take into account how much a move reveals about the rules of the game when balancing them.
  • Most modern video games are designed to teach you the rules during your first game (which may actually be an obstacle if you want an exercise where the rules are taken as known)
• My impression is that most games with exploration as a mechanic are optimized to deliver feelings of discovery, rather than interesting strategy around explore/exploit trade-offs.
• Any game where information is valuable, and where gathering less than the maximum amount of helpful information is a viable strategy, is a game with a significant amount of luck.  (Since this implies you can gamble on unknown information at reasonable odds.)  This means players who only play once will not have a reliable measurement of how well they actually played.

You may be looking for traditional roguelikes! If you search for old BBS archives of when the term was coined, you'll find surprisingly little mention of integral concepts like "permadeath" and "procedural generation", instead everyone's talking about portability and FOSS. Many modern -likes (not -lites) retain that focus on simplicity, and Discord has been very nice for this community: can often talk to the devs weekly if not daily, so the games don't remain too difficult/easy/solved for too long.

My personal recommendation is The Ground Gives Way:

1. on the shorter & simpler end for long-development titles
2. VERY beatable on first run (with patience & after ~15min tutorials), while consistently difficult for reasons other than localized unfair/unpredictable variance

Note that full wins in RLs are def closer to 2h mark or longer, if thinking about every individual decision, especially when reading through monster descriptions to learn the game. I can play a few of these games at 30min pace while maintaining ~90% winrate, but learning exactly when you can spam commands with miniscule risk takes hundreds of hours.

I will also second Brogue, which is only a bit longer & more complex. And echo StS even if it's not a roguelike, pretty good fit but Ascension-0 or 1 is def too easy, A-20 runs should be closer to what you're looking for.

This is a simple strategy game that's so old you'd have to run it with an emulator. I think it did a good job of explore/exploit and hidden information though. Later versions were increasingly complex, but I actually think the original makes for a good time-limited pure strategy game.

https://www.macintoshrepository.org/5762-starbound

[Edit: there's a link on the page to play the game in an emulator that runs in your browser window.]

I would probably have suggested roguelike deckbuilders too if others hadn't already, but I have another idea:

Start a campaign of Mount and Blade II: Bannerlord, and try to obtain at least [X] gold within an hour.

Bannerlord's most flashy aspect is its real-time battle system, but it's also a complicated medieval sandbox with a lot of different systems that you can engage with - trading, crafting, quests, clan upgrades, joining a kingdom, companions, marriage, tournaments, story missions, etc. Even if you're no good at battles, you can do a lot by just moving around on the world map and clicking through menus.

The game's community derides a lot of these systems for being simplistic and unbalanced. But I think that makes for a good explore/exploit tradeoff when you only have a short amount of time. What systems do you bother learning about, when trying to learn a new system takes time you could be spending exploiting the last system you learned?

(I'm not sure what the right value of X is, for the amount of gold you're trying to get. Ten thousand? A hundred thousand?)

One downside is that the game involves an action-oriented battle system. If you don't want action gaming skill to be a factor, you can remove it by requiring the player to auto-resolve all battles. But this would cut out many viable early-game moneymaking strategies.

Seconding Slay the Spire, though it might be slightly too easy to win on the first attempt (I did and I'm not a god gamer). An advantage of StS is that you can specify the RNG seed, so you could give everyone the same test.

FTL (another roguelite) on easy difficulty also might work, though it's realtime with pause which might be tricky for less experienced gamers.

Both of these are games that benefit a lot from thoughtfulness and careful risk management.

Deck builder rogue lites maybe. Slay the Spire, dicey dungeons etc.

Slay the Spire, unlocked, on Ascension (difficulty level) ~5ish, just through Act 3, should work, I think. Definitely doable in 2 hours by a new player but I would expect fairly rare. Too easy to just get lucky without upping the Ascension from baseline. Can be calibrated; A0 is too easy, A20H is waaay too hard.

Universal Paperclips is the first thing to come to mind (the fastest Speedruns are ~1.5 hours but finish the first 2 stages in ~1 hour, and the time to complete each stage is a decent milestone for measuring people), with the problem being that you can't lose; you have as much time as you need to to explore the mechanics. Any mistake will only slow you down, the worst thing that can happen is a single occasion where you lose one single point of trust, you never get shut down by the humans even if you mismanage the wire extremely terribly at the very beginning and completely run out of resources.

Recently encountered a game that made me think of this thread.

King of the Bridge is a game where you play an unfair chess variant with partially-secret rules and the opponent sometimes cheats.  I reached the first ending in ~40 minutes.  Getting there without ever losing a match seems like it ought to be possible with great paranoia plus some luck.

If you want to try this you should probably avoid looking at the store page in detail, as some of the secret rules are revealed in screenshots.

Long Live the Queen takes about 4 hours. It would take some luck to beat it on the first try, but generally you win by using common sense and training useful skills.