I'm looking to run an immersive/ARG style LARP and I'm trying to block out the time that I'm estimating players will spend on different tasks. One part of this is going to involve puzzle solving, and there is a puzzle which can be solved, but isn't central to the main plot (so the players don't HAVE to solve it). I'd like to know if you guys have any good way of guesstimating the difficulty of a puzzle/mystery or how you plan this thing since I have a finite amount of time to work with and don't want to generate too much content.
As previous posters have said, you'll get a huge variation in the time taken to solve the puzzle.
If your puzzle is basically a maths problem, or can be brute forced in some way, you can make a ballpark estimate. Figure out how long it would take you and assume a spread of about 50% - 200% of your time. The more players you have, the more likely the time is to be towards the lower end of the range.
For anything which involves some intuition, you really can't make a reliable estimate. It all depends on whether any of your players think in the same way you do. At a weekend long LARP for 100 players, I've seen puzzles of this type we estimated at 2-3 hours be solved in under a minute and other puzzles we estimated at 10 minutes not be solved at all.
Looking at the second part of your question - "how do you plan this thing" :
1) Since this puzzle isn't central to the main plot, make sure it can be worked on in parallel with the main plot without tying up a significant proportion of the player base.
2) If you would like to see it solved anyway, have one or more clues available for the players to find as they progress down the main plot line.
3) If it is obvious that this isn't part of the main plot, be prepared for the players to totally ignore it.
There are two basic ways.
- The hard way: playtest your puzzles. It takes time, it is rather inaccurate, but if you invent your own one, you need to do it at least a couple of times.
- The easy way: take ready puzzles and adapt them to your needs. Gotcha! All the work already done for you by someone else! I love this way.
As others have noted, be prepared that some players will take considerably more time to solve the puzzles, and some will take considerably less.
It should be noted that even if your puzzle is open-ended, you still need expectations. For example, let's say that you make a list of 50 questions and give 20 minutes to solve them. If they are too easy, you may find out that all of your players chew through them a lot faster than expected, e.g. in 10 minutes or quicker, or, if the questions are too hard, you might see that the amount of solved questions is generally too low to determine winners.
So, always have an estimation of the time needed to solve the puzzle!
If you set a specific amount of time instead of leaving the time open ended, you have just effectively sealed off how much time it will take to accomplish a task. This means, however, that you will have to measure success or failure in a different manner, such as with quantity or quality of work. Puzzles involving different configurations, searching for words/images/differences, or alternate solutions to problems would seem to be appropriate for this sort of timed puzzle venture.
If you want to go outside of the box, you can have players do an action that is similar in hand or body movement accomplish another task. ( "Pick this lock? Tie knots in this string. You have 45 seconds.")
If you REALLY want to go outside of the box, you can have the players perform a symbolic action or set of actions to accomplish the task. The action could/should allow for others to assist in the action, and I highly reccommend that the addition of assistants make the action performed exponentially more hillarious. (I,e. Lockpick plays GM in a game of Connect Four. Assistants have to try to tickle the GM with feathers to assist the Lockpicker. Gun-slinger is taking aim at an opponent in game, but out of game he has to hit a target with a pool noodle. Anyone assisting has to hold a pie for the gunman to hit with said pool noodle.) This increases fun for the entire room, especially if the participants don't mind hamming it up. The game within a game also keeps things fresh.
Mr Puzzle gives this explanation for physical puzzles.
Difficulty rating 1 are the easier puzzles to do and memorise. Difficulty rating 10 is the most difficult to do and memorise. Puzzles rated 1, 2 or 3 may not take hours to do but there will always be some challenge involved. Don't write off these puzzles as too easy for adults. For a puzzle to be rated a 9 or 10 it must be VERY difficult to complete the puzzle, and VERY difficult to memorise the puzzle's solution. For example, a puzzle rated 7 could take an average person a couple of hours to do and then memorise. A puzzle rated a 9 we expect that most people - say 80 % or so - will NEVER be able to master the puzzle without assistance from the solution. How we present some of our puzzles will also have a bearing on the rating we give them. Some of our Interlocking puzzles are sold apart which adds the challenge of having to put the puzzle together without having first taken it apart.
The youtuber, Chris Ramsay solved a level 10 Lotus flower puzzle in around 41 minutes. He does those puzzles professionally and has a lot of experience.
If all of your puzzles are Level 10, as above, you can expect the average person to take longer than 41 minutes, up to more than a few hours.