In a fantasy RPG, do you have any experience with a simultaneous initiative system?

Imagine that everyone has a quick time limit to declare their actions.  Then it all happens simultaneously.  Everyone rolls dice to hit and damage and DM narrates the results.

I know there could be outlier exceptions that might prevent this, like under a spell that slows - that's not what I'm asking about at this point.

How did it go if you did this or something like it?  Opinions and experiences are appreciated.  Thanks.

That's similar to what I do although I don't have a time limit for the players to speak their actions. But, essentially, things happen simultaneously but if there is an issue, I have a die roll off to decide who's action happens first (or I just use their attack rolls and the high roller goes first).

As far as how it goes, that's a bit of a hard question. it works just fine and if you had never played an RPG with sequential initiative, you wouldn't think it was strange.

One thing about narration though, is that I generally narrate the entire battle rather than narrate each individual action. For example, if the players as a whole rolled really well, I'd narrate how they drove back their enemy. OTOH, of the players rolled badly, I might have the bad guys push them back and drive a whole in their line. That change in the narrative focus is the most significant shift game play wise as it typically doesn't matter who goes first in a normal fight.

I did try a simultaneous system in a forum game once. I got all the players to put in their moves and then resolved the actions as if they all happened simultaneously. I seem to remember it worked quite well from a DM perspective, but my players revolted as they always wanted certainty on the outcome of their actions before they committed to a roll. Which was the exact this I was trying to avoid as that is the main thing that slows down a forum based game. So although it worked, it actually ended up being slower than just going from player to player.

Hedgehobbit, I was thinking that the higher roll would go first, like if the bad guy and a PC were both scrambling from opposite directions to grab the key near the chasm opening.  Higher roll would get it partly because that guy got there first. If they both rolled well, higher roll would get it, but maybe there would be a scuffle.

Mightybrain, do you think if you used that system a few times, it would not go longer?

Traveller had simultaneous initiative.  It worked out fine.  Everybidy was always trying to get the jump on their opponents.  Kinda like real life.

I tried. Everyone declares intent. One roll. Natural 20? fine, you attack first and you crit.

It works well, but makes things a bit chaotic. I still like this better than "rolling initiative".

https://methodsetmadness.blogspot.com/2020/09/minimalist-d-vi-super-fast-5e-combat.html

Currently I'm playing Shadow of the Demon Lord and using "the PCs act first unless there is a reason to believe otherwise" (they are surprised etc.).

You can also do phases - which is a bit of a mix. Works better with side-based initiative, and the melee can be simultaneous if opposed attack rolls.

As a player, I've used simultaneous initiative in Burning Wheel. You have a sheet full of options that you check off. A bit board-gamey, but fun.
As a GM, I've used simultaneous initiative in Lamentations of the Flame Princess. I had players write down their actions on index cards and reveal them at the same time. Players wanted to be able to script actions. I allowed one if/then conditional plus a single else.
As a game designer, I've playtested my game with a variation of Rune Quest's strike ranks system, but it didn't work so well. I've dumped it in favor of an initiative pass mechanic, similar to Shadowrun, but I've yet to playtest it this way.

I find that simultaneous initiative can make combat a lot deeper, but it can make tactical positioning a little fucky. Either use 'theater of the mind' and very inexact positioning, or get really, really exact about positioning. I like using chess boards as battle maps as they allow the use of chess notation. Chess notation makes it very simple to clearly and concisely communicate movements and positioning, if you don't mind the limitations of an 8x8 grid. You should play Diplomacy if you haven't already (I hate playing Diplomacy, and I swear that I will never play it again as long as I live, but I'm glad I played it at least once). That game uses simultaneous action. You should mine it for ideas.

At one point or another, I've done about every initiative system imaginable--with the possible exception of some of the variants on rotating "ranks" where your initiative spot changes based on what you did last.

Whatever your initiative system is, it should take into account the sequencing of the actions of the characters and the conveying of the information between players and GM and back again.  That sounds obvious, but if you break down what is happening, characters and players often have different needs.  I say that to preface that some form of semi-simultaneous initiative is my preference but you need to break up player reporting into chunks in order to handle communication--chunks bigger than 1 person (usually) but not more than 3 to 4 people at once (depending, however, on GM tolerance).  That can be something like some of the early D&D systems with melee, missile, and magic being different phases or it can be some other divide. 

Everyone declare and then everyone reacts requires that the players be trained to do that.  It's not a natural flow for some.  You still need a phased means of accepting and giving information even so.

In Fighting Fantasy, combat is just an opposed roll. There is no initiative.

Even though it originated in a choose-your-own-adventure gamebook series, it works well enough. I have sometimes wondered why more games don't take this approach.

Quote from: Vic99 on July 19, 2021, 04:21:52 PMMightybrain, do you think if you used that system a few times, it would not go longer?

My players are creatures of habit. I imagine if I hadn't dropped it years ago they'd still (years later) be complaining about it during every combat. However, if I ever get around to making my own system I might make it the default system.

Here's the DungeonCraft version:
https://www.youtube.com/watch?v=y_mxYKzEjms

IMHO, for d20 based games with AC it is either this or Group initiative.

Even for his Group initiative I like the timed declaration phase he still uses:
https://www.youtube.com/watch?v=gZ89m4fD2p4

A timed declaration phase is much better for keeping things moving. Yes players are technically declaring their move twice, but the point is that once they declare their action they can't change it!!!

Just go around the table resolving actions, bam, bam, bam, bam.

Saves time from players having a new debate on the optimal thing to do every turn. And the timed declaration keep analysis paralysis to a minimum.

One thing I do at my table is I don't roll initiative each turn. Instead if one side does more damage in a round and they do not have initiative - I have them win the initiative.

I've been looking for a simpler initiative and also something to try and get the players actively involved in combat. Turn to turn inertia and over-analysis are major causes of combat slowness.
This gave me an idea:

Quote from: Jaeger on July 20, 2021, 11:55:50 PM
One thing I do at my table is I don't roll initiative each turn. Instead if one side does more damage in a round and they do not have initiative - I have them win the initiative.

I am going to try a momentum-based Initiative.

QuoteUnless surprised, the PCs have initiative, and they may act first.
All characters on a side may act and their actions are considered simultaneous.
During the turn successes are tracked and the side having the most successes will have initiative for the next turn.
Successes are any action that does damage to an opposing side, negatively affects an opposing side or benefits the character's side.

This will hopefully encourage players to make active choices and pay a little more attention to what is going on in combat outside of "their turn".
Also, if one side is outnumbered or facing a high-powered threat they will likely lose initiative quickly. This should highlight the danger to the characters and encourage some discretion concerning fight or flight.

Quote from: Marchand on July 20, 2021, 11:11:33 AM
In Fighting Fantasy, combat is just an opposed roll. There is no initiative. [...] I have sometimes wondered why more games don't take this approach.

It'd take some thought to organise it if someone wanted to take a non-combat action in that round.

Quote from: Kyle Aaron on July 21, 2021, 10:59:37 AM

Quote from: Marchand on July 20, 2021, 11:11:33 AM
In Fighting Fantasy, combat is just an opposed roll. There is no initiative. [...] I have sometimes wondered why more games don't take this approach.

It'd take some thought to organise it if someone wanted to take a non-combat action in that round.

It's a very rules-light system so on-the-hoof refereeing is expected. Characters only have two "active" stats that they can use to do things, SKILL (with special skills added if applicable) and LUCK (and MAGIC if a magic user). So an opposed SKILL roll against somebody trying to hit you would work in a lot of situations, or a LUCK throw if your chances seemed more down to luck than skill.

Say a PC is trying to grab a rope and swing off a ship before a pirate chops them with their cutlass. That could be the PC's SKILL+Dodge against the pirate's SKILL+Swords. I might let the player argue for SKILL+Seamanship if they had it. Or I might just let them test their LUCK (although each test costs a point, so it is a diminishing resource).