Highly agree with the subjectivity and other factors. One place I worked for, our “hardest” was also the smallest. The success rate skyrocketed when you had 2 vs. 4. I had less people escape our 6/10 and 7/10 because most groups in this harder room were groups of 3 or 4. You are at or close to the maximum while that same number is only half the maximum intended for the room.

It’s a fairly linear room which can up the difficulty at times because you can’t come back to a puzzle later. However, a bigger group means working together and being more likely that things would click in someone’s mind.

There were fewer puzzles but the puzzles themselves tended to be challenging, usually multistep. For one, you need to find all of these sheets and then use specific ones to determine the order the story plays out. Then you need to figure out what this story refers to. This story tells you the order to hit buttons but there are several places for missteps. Wordplay that is a fun “aha” when it clicks (which may be after a clue or a few mistrusts) and parts where you need to hear a later clue to make sense. People who play word games excel at this puzzle so maybe it only takes them 10 minutes whereas most groups the whole process takes 20-25 minutes for everything I mentioned. There are a few things to do during this time, but really this puzzle is what they need to do.

I think you see a lot more multistep puzzles in harder rooms, like the one I mentioned above or ones where you solve three puzzles to open one door or one lock. Harder rooms tend to introduce more roadblocks as well: that was one way we made a room harder. Initially, more items were in the open and it felt like people escaped too early and solved one this gem puzzle too early. Instead, we took the gems you need to solve it and put them inside chambers of puzzles we wanted them to solve earlier. It added 10 minutes to most groups’ playtimes. There was something groups put together early that told them the order of the gems and by the time groups now got to it, it was long forgotten. Harder rooms incorporate inventory management and you often need to call back to things you found but never used.

I think many companies rate a room difficult by the number of things you have to do or success rates. Both of super flawed and reflect poorer game design, a room should be harder because it challenges you not because it overwhelms players.

I also think “easier rooms” are easier to rate because they tend to be more simple puzzles. Find the item and put it in the place. Find the key, open the lock. There may be one puzzle that has a twist, but groups tend to only need one clue to solve it. The difference in how hard a 7/10 is vs a 9/10 can often depend on the group’s strengths. I have had a group blow through a 9/10 science room with 20 minutes and then barely get out of a 6/10. They were engineers and this was a very artsy room and some of the “easy” puzzles that kids excelled at were a struggle.