Having watched many videos of Mario Maker 2 troll levels, one thing I've noticed is that sometimes they use hidden or reverse time limits, and sometimes these appear in other games as well (particularly reverse time limits).

A hidden time (or turn) limit is when you have a limited amount of time (or a limited number of turns) to do something, but the game does not tell you that. Hence, an unsuspecting player might take their time, only to be caught off guard by the time limit. Less trolly games might at least hint about this (for example, in Final Fantasy 5, you might be told to take the spell quickly, and while no timer appears on screen, if you wait, the game will end).

A reverse time (or turn) limit is when, after a certain amount of time, the game allows you to progress. In a troll level/game, this can punish players for going fast; doing so causes the player to go past a one way section, but the player actually had to wait before that for another path to open up. A non-troll example is in the final army battle in SaGa Frontier 2, one that's notoriously difficult; if you manage to survive to the end of turn 8, the game gives you the victory. (Note that the SaGa Frontier 2 example isn't hidden; it's listed as a possible victory condition. Also, I'm pretty sure other strategy games have done this sort of thing.) Or there's the boss timer in Touhou games and some other bullet hell shmups: If the timer runs out, the boss fight will progress to the next phase (though in Touhou you forefit the spell card bonus unless it's a survival spell).

So, what do you think of these mechanics? Do you like them, or do you think their bad? Or do you like reverse time limits (particularly when they're not hidden), but dislike hidden or even visible regular time limits?

I hate any sort of time/turn limit in my games.
I want to play games in my own tempo.
That's why I usually don't buy games, of which I know that they come with time/turn limits.

Hidden time limits are bad, definitely a frustrating mechanic. Even if it's not "realistic", time limits need to be communicated to the player.
I don't see that much of an issue with "reverse" time limits, there are many scenarios where they make sense ("hold the line until reinforcements arrive/the wonder is built/the superweapon is fully charged") and can provide good gameplay variety.

Most CRPGs usually should have no time limits, and certainly no hidden ones... unless the game really goes about them transparently and deeply.

"Reverse time limits" are things I've only encountered a few times. They could be done well or not, but usually could be done better by other check points than "time", or at least have an override with time as a backup unlock to boost players who may be struggling. It's usually tied to unlocking a new area or system (or, as you said, basic progression). They can easily lead to frustration with "I guess I just have to leave the game on and waste time until it comes along" if not tightly designed. ("After X amount of time, or after X plot progression point, steel weapons rather than just iron weapons become available for purchase.")

Your example of Schmups with boss fight time limits after which point they fly away is terrible. Every time it triggered for me, I felt terrible and hollow, worse than if I had died.

On my fairly recent play-through of Powerslave I got hit with a lovely hidden time limit in the last level. Apparently, the game gives the player only 15 minutes to finish it before giving you an automatic game over. At first, I thought it was a bug or I hit some in-level switch I was supposed to, but after several reloads it was apparent it was due to no fault of my own, so I had to look up online to see why this was happening. I'm pretty sure I was close to completing it, too. Yet that bullshit pissed me off so much I was done with the game for good. I don't put up with that kind of dumbfuckery.

I'm not the biggest fan of time limits at the best of times - I like to play my games at my own pace, thank you very much - but when games can't even fucking bother to let me know that there even is one and inform me how much time I've got left I just want to slap the shit out of the devs with an extra-large, frozen trout.

Related:

I really am unhappy when a strategy game has a stage/mission that requires a rush strategy. I'm not a "rush" player. And it's often made worse because sometimes they're built with very low tolerances of "rush", which is to say, not only do you need a rush strategy, but you need a well-executed one, to complete the map. Oftentimes these stages don't even communicate to you this requirement.

Examples:
* Numerous stages of Ages of Wonders 3. I stopped playing because of this.
* Dungeons 2 later levels. I was forced to use cheat codes.
* Dungeons 3 has some "rush for bonus objective". I still can complete them, I just can't "gold star" them without the rush. Fortunately, as far as I can tell anyway, there's nothing hidden behind gold-staring stages other than personal satisfaction.

Some games use their time limits for the better.
Like the Pathologic games or the Dead Rising series. But to be fair, Pathologic is more like a time manegment game then anything else. And people do like it for this.

And to be honest, I do find it strange that in most RPGs nothing is time critical. Like the child that has gone missing in the woods and will be surrounded by wolfes at day 1 and day 100.
But at the same time I hate when I have to rush quests because of a time limit...

The other kind of time limits I do know from some MMOs like Star Trek Online.
They got spawnpoints there, that are active for a certain amount of time. Players use this for XP-Farming, while blowing up whole fleets of enemy ships.
It is not told to you, if a spawnpoint does have a timelimit or how long it will last.

I always hated the mandatory rush in Fantasy Wars.


Edit : I'll add that the hidden victory in Saga Frontier 2 was a godsend. I don't think I've ever taken on Fake Gustave in the army battle.

This doesn't sound too bad. It also doesn't sound hidden. While the precise countdown isn't available, you're told it's there, and you're given a check-in. It also doesn't look like it's game-breaking to miss it. Aye, Dead Rising is built entirely around a time limit and multiple play throughs. I suck at it, and would certainly enjoy the game a lot more if the time limits were more forgiving for a crappy player like me. It's different when the game is built around time limits than only using them at certain parts.

NEW MATERIAL [not related to quotes]
Another "reverse time limit" in numerous games is "survive X turns/minutes/battles" to progress. I'm way more OK with these than other time limits. Sometimes you're immediately in an onslaught and it's bad (but hopefully you're given resources to recover rather than requiring perfect play). Sometimes (especially in RTS games) they go on too long. "Survive an hour." Really??? Yes, RTS sessions tend to go long (even well past an hour), but when you're making it the goal, compact it and make it exciting. Especially in case of failure!

Honestly? They're terrible mechanics. Time limits place a restriction on how to play a game, and as far as I'm concerned never have a place in video games. I also hate reverse time limits; make it mandatory to develop certain skills before progressing fine, but an arbitrary "you must play for x hours or turns" is just ridiculous. The only exception for me would be an RTS or something "build your defences for the enemy attacks in 10 minutes".

All time limits are bad and they should be made to sit on the naughty quantum step.

I generally don't like time limits, but even less so when they are not clearly communicated and are rather short and harsh on top of it. I just had this issue with a quest in Divinity OS EE, and I actually KNEW that there was a (vague) time limit, because I had read about it in a walkthrough, so I tried not to waste too much time, and yet I still managed to screw it up (reloading and immediately racing towards the quest giver fixed it, but that was bullshit).

I also hated it in Baldur's Gate when Minsc suddenly turned hostile towards me because I didn't solve his quest fast enough, and the threat of the time limit in Fallout also prevented me from really enjoying exploration in the game, so to this day I've never really played it for long (I hear the time limit is generous and nothing to worry about that much, but it stressed me out regardless.) And I stopped playing Blackguards due to a time sensitive mission that you have to beat in 5 turns, because it was extremely frustrating how relentless that limit was, when RNG constantly interfered with your tactics and a single miss could mean the attempt was bodged already and you'd be better off restarting the whole combat.

If there is a time limit at all, the player needs to be able to judge the urgency and level of threat it poses and to take appropriate measures. The challenge has to be easily comprehensible and manageable. And when a story demands urgency, it's counterproductive if the game distracts players with loot containers, collectables or other incentives for exploration.

I agree that the :"hidden victory" is definitely a good thing, though I'd argue that it's not hidden, as if you look at the victory conditions, it's clearly mentioned.

Also, the trick to defeating Fake Gustave is to surround his unit with your units (best way to get behind him is to have one of your units retreat after being attacked; the game has a funny definition of "retreat" sometimes), put archers in range, and have all 4 units attack the Fake Gustave unit in order to force it to retreat. If the defending unit is forced to retreat and has nowhere to go, it's treated as defeated.

With that said, the "survive to the end of turn 8" victory condition seems to be canon. Furthermore, if you just want to beat the game, you don't even need to play this battle! (The only thing it gives you is the ending to the Gustave side of the story, but beating the game only requires beating the Wil Knights side; then again, the final boss of the Wil side is notoriously difficult.)

I agree, and I'd argue that this should be done for normal time limits as well. Super Metroid Redesign's final escape sequence, for example, goes on way too long (I think it's something like a 25 minute timer).

Make timed sections short, find a suitable time limit, and if it's a normal time limit (time up = failure), add a minute or two as a cushion (without making the level longer).

Also, screw things like this:
https://finalfantasy.fandom.com/wiki/Excalibur_II#Requirements