reverse out of depth clock

[HardboiledGargoyle]

The reason to move on to the next level is actually "there is nothing to do on the current level", for most people. Sometimes you have nasties on your level, which just means you'll progress more efficiently by diving a little, then coming back up. Extending this logic to make a functional clock, you need to make the player race against ending up with nothing to do on the current level. Make monsters leave the current level if you spend too much time there, only to reappear in the next level you visit, where you'll be at a disadvantage due to being on a new and unexplored level full of baddies. There only need to be provisions against letting the player walk from D1 to Z5 without confronting anything.

[dowan]

That's certainly an interesting take, but I think the monsters would have to take the items and shops with them, otherwise I could gather myself lots of free loot early in the game, then use it to clear the extra packed floors.
It also has the issue of making it seem like the player is doing OK until suddenly they realize there's just no way in hell they're going to be able to clear the next floor, but that's not that big of a deal, and theoretically hunger has the same issue.
I would think at branch ends you could prevent this from functioning, so if you took forever clearing the D levels, you'd end up with an insanely packed D15, although I suppose most of it would be popcorn since it's a lot of monsters from earlier on...
It would be deadly in the rune branches, imagine all the snake enemies packed into snake 4!

So I am interested in the concept, and would like to see it fleshed out a bit more, but I think you do need to consider the problem of, for example, an xl1 character just 'diving' spending enough time on each floor to clear the baddies out, then gathering up all the loot. A free, if boring, ticket to midgame is problematic. But just having the loot move with the enemies could fix that.

[VeryAngryFelid]

Make monsters leave the current level if you spend too much time there, only to reappear during orb run.

FTFY. Otherwise it's just free meat shield from dangerous monsters and Ru/Qazlal/(Makhleb with axe) buff.
Having low XL can be a problem as hellcrawl shows.

[dowan]

That's interesting, but depriving slower combos of XP leads to a real snowballing problem. You were a little weak on D1, so 1/4 of the enemies vanished. On d2 with 3/4 of the XP you should have, you were only able to kill 5/8 of the monsters in time. Now you're on D3 with... I dunno... 11/16 of the XP a faster combo would have, and thus kill less monsters, increasing the snowball effect.

At least if you keep pushing them down a level the XP isn't lost, it just becomes more dangerous to gather.

[HardboiledGargoyle]

To have a functional Crawl clock it is sufficient to only to punish taking an absurd amount of time doing crazy stuff like waiting on stairs for all the level's monsters to come to you ("making it seem like the playerscummer is doing OK until suddenly they realize (that it's pointless, plus) there's just no way in hell they're going to be able to clear the next floor"), so it may be lax enough for weak characters to inch through before monsters start leaving the level.

If the monsters leaving to next level are awake and wandering on that level, then pretty soon you won't be able to peacefully wait on a level that still has monsters on it.

I don't think branches necessarily have to be kept separate. Monsters can already generate in adjacent branches, e.g. D spawns on the L:1 up-stairs. Plus, it's not a big concern if Crawl gets a rather linear structure, which is not off the table if we're discussing mechanics as deep-rooted as ood spawns.