Riffing off of that, I'll say that Felltower is all about consensus.
One benefit of a pick-up, large-player-pool bounded sandbox game can be individually set goals. You see this in the West Marches:
Players send emails to the list saying when they want to play and what they want to do. A normal scheduling email would be something like “I’d like to play Tuesday. I want to go back and look for that ruined monastery we heard out about past the Golden Hills. I know Mike wants to play, but we could use one or two more. Who’s interested?” Interested players chime in and negotiation ensues. Players may suggest alternate dates, different places to explore (“I’ve been to the monastery and it’s too dangerous. Let’s track down the witch in Pike Hollow instead!”), whatever — it’s a chaotic process, and the details sort themselves out accordingly. In theory this mirrors what’s going on in the tavern in the game world: adventurers are talking about their plans, finding comrades to join them, sharing info, etc.
This is not how Felltower works.
For Felltower, it works this way:
1) GM and players decide on the next game date. This used to mean the next time at least a few people and I could play, but now means the next time almost everyone can make the game.
2) Sometimes by email, but usually on the game day itself, the players discuss what to do.
3) Verify with the GM that this is ready to go.
4) If 3 is satisfied, play. If not, go back to step 2.
We almost never have individual-led expeditions as described in the West Marches game. We don't get a lot of, "I want to sack the Black Library on 8/4. Who's coming?" and lot more "We're playing 8/4 and everyone except (these two PCs) can play. Where should we go?"
That was not how it was designed, though.
Originally, it went like this:
1) GM decides on the next day game can be run, with input from the players (since one of them hosted game.)
2) Anyone who can come, does come.
3) Players decide what to do.
4) Play.
It's a difference that has led to a much more traditionally style of game. We play when everyone's around, game frequency has dropped off as real-life concerns are compounded by the perceived need / desire to have almost everyone there, play is purely cooperative (no one is trying to raid location X without cutting everyone else in), and the game has grown more tolerant of multi-session delves.
Some of that is Felltower itself at this point - there are less hanging tag ends to pull on. Or at least, less that the players see and perceive as a potential way to get loot without dying. But it's been a consistent theme since early on. It's decision by consensus, not individually led sessions. PCs don't start as somewhat trepidatious weaker delvers and, as they grow stronger, branch out into individual goals and individual delves. Instead, they start out as somewhat trepidatious weaker delvers and grow into stronger, more and more group-oriented delvers. Regardless of how powerful they become, they continue to work together as a group and make decisions about delving as a group.
There are pros and cons, of course.
The pros are largely convivial play amongst the players. We don't have a lot of in-party conflict because we have players who either started as friends, or became so because of the game. It's almost always fun, no matter the result of the game, because everyone gets along. This pro doesn't take long to write out, but make no mistake - this is huge. Anyone who has played with That Guy knows that not having That Guy makes for a better experience. It's why I recruit friends, not gamers, into the game. At least gaming group has spun off from my group, with players who met playing Felltower (or the previous game I ran.)
But it does have downsides.
The main downside to consensus is that everyone in my group generally has to agree on a task. Or at least, not be opposed to it. So preferred play style / play tolerance dictates actions. We have at least one player who vociferously objects to purely exploratory or preperatory sessions. No filling in the map or just checking out some side areas or making sure of some half-checked areas. Bold delve or no delve. So when that player is around, those things can't happen . . . so they generally don't. We have some risk-averse players, who'd rather a sure thing than a long shot, and so that cuts out some high-risk high-reward options. There are others, too - some players are just either not interesed in mid-week email-based planning (or Discord based, assuming they're still using their Discord channel), or don't have time for it. So delves that require some planning don't get planned, and the "no pure planning sessions" guy won't spend Sunday on that, and the "no risk" guys won't go without planning because it's too risky, and no one seems to plan by email because they need full consensus to go.
One reason the last session's delve into the Brotherhood Complex had all of two hirelings - I don't think they even tried to hire Darkspire - was because I didn't have any more set up in the VTT. I didn't make any because no one affirmatively declared they'd go and hire them, and I don't do prep work for PC-centric actions like that on a maybe. Why didn't anyone declare affirmatively they'd hire them, even with a caveat of "when we go, which isn't decided yet*"? I do not know, but I think it's connected to this idea of consensus. Everyone didn't agree this was a thing to be done, so no one did it.
It even has some direct "off limits" results for Felltower. Black library? Not with a cleric, because they'll burn the books, but not without a cleric, because you need healing and curse mitigation. No dragons, because not everyone is on board for risking a grounded fight against a flying monster. I'm partly sure we lost one player because the whole "yes you have to roll for every door" style of play of Felltower annoyed him, and no one wanted to spend the time - least of all him - to knock down doors or fix broken entrances and such to make that a non-issue.
The game has changed as a result. It's still supportable, but it has had consequences. Less gaming sessions overall - a month with two game sessions is a good month. It used to be standard. It's not uncommon to miss a whole month. Players used to complain about how long it took to special order items and get enchantments done, but now they complain about lack of funds more - time between sessions is longer so the first is less of an issue but it takes big hauls each of the delves to net the same cash over time. More concern about TPKs and dead PCs, because losses are a more significant given less actual time to play and way a fallen PC falls out of a niche. Groups come together more as "What do we need?" and less as "I have a character idea." It resembles a lot more Session 0 in a traditional game than a pure pickup game would.
So concensus isn't all a bad thing - it does mean more player enjoyment and better cohesion as a group. But it does affect how Felltower is played.
* I'm still not doing the prep just in case, so it better be damn firm before I spend my non-session time loading up a bunch of NPCs and tokens and so on on a maybe. It's annoying work at best and wasted time consumption at worst. I'll do it when I have to.