The Mother of all Learning (time loop) campaign

I have an idea of using a fixed space (castle/cavern/manor) where the party must overcome an enemy that is able to TPK them with all their minions and power. However the party is not the main target of the BBEG, they are just in the way. Here's the twist, at the end of the 1st confrontation with the BBEG and their rival the party is all killed only to wake up several hours (1 day?) before the conclusion. This repeats with each time any of the party dies or they reach the finale point in time they are sent back again.

The idea is to get the party to figure out as much as possible during these time loops so that when they finally leave the loops they can systematically dismantle the BBEG's plans and traps.

I want to limit the # of loops but still give them enough time to figure things out. By keeping the PC confined to the fixed place, NPC move beyond as if in the real world, along with all key information and possible solutions I hope they can work out how to overcome the BBEG. The idea is that the NPC in the loop act as if it is all real but it is merely an advanced illusion mixed with time magic that facilitates learning information.

Questions:
Do the PC gain experience from the time loop?
How long and how many loops should be allowed? I want to limit it and introduce the limit to the PC so there is a sense of urgency but still some hope to overcome BBEG and avoid TPK when the loops complete.

Any additional feedback, suggestions, or references to any similar campaigns would be appreciated

I think this sounds like a pretty fun campaign concept.

Personally, I would say no experience gain, focus only on their different approaches to the situation, not any new abilities they gain. But I also don't really care about leveling up in games. I know it's a more important factor for other people.

As for the number of time loops, I think that also depends on how long each time loop will be until it ends. I assume the first few loops will end with very quick deaths, but if one loop takes out half a year in pbp to play out, then aiming for twenty loops might be unrealistic.

"Dormammu, I've come to bargain."

Death. Save. Repeat.

It is module I posted in my wondorous one shot interest check. It is basically this idea but it just worked as a one level adventure.

@valdattaMadun : Have you ever run or been in such a game?

Read the module only

More details on how it works.

It was basically a 20 turn in initiative time loop with an hour/hours before the events start. Essentially having lair action like events that happen on specific events the players are attempting to stop/alter.

The odds are steep from the beginning and they edge their way to the finish line each retry/alternate paths for successful tries. But keeping "what if we did this instead " always in mind

Thanks for the info. I have been considering an external/secondary trigger that would not have happened on the initial timeline that their changes to events could trigger. Now the tough part of finding ways to put the puzzle pieces in the PC path without being too blatant or convoluted.

Sounds like a cool idea. I haven't read Mother of Learning, but I did read another web fiction about time loops called The Perfect Run that I liked.

One thing I like about that one is how the protagonist values his life (or more accurately, values his value of life), doing his best to survive and see a loop through to its end, instead of brute forcing any given problem through a bunch of deaths. It keeps the stakes higher and leads to more interesting loops due to the greater amount of divergence compared to if you were to keep restarting at the first inconvenience.

That's a good idea to have some kind of bonus for surviving to the end of a loop without dying. Thanks