Nareau said:
Thanks for all the great advice! I'm thinking it's solvable, but may be too convoluted to actually be fun. If y'all have any ideas on how to make it more interesting/fun, I'd love to hear those too.
Here's my thoughts.
First, to be blunt, you need to pretty much outright ignore some of the comments made here about the puzzle being "unsolvable" or too confusing. If some of the people saying that had put anywhere near as much effort into actually analyzing the symbols as they did discussing how it was "impossible" to do so, it would have become obvious that this was a basic substitution. The actual translation would have been a lot more difficult, but they could have at least found the right path. Any time you present a puzzle to a group, there has to be the basic assumption that they will try and solve it, and not give up until they have exhausted all possibilities. If someone isn't going to bother at least trying, it doesn't matter how easy/hard the puzzle is.
As for the actual text of the puzzle itself, I think you did a pretty good job. I absolutely loved the way that the first line of the puzzle had two three-letter words that ended in "e" but were not "the". It definetally keeps people on their toes, as shown by some of the attempts before mine. Choosing words that use uncommon lettes and avoiding common letters (like how you used "w" four times, but "u" only once) is very fun IMO. Keeping the text short and to the point is also good, as substitution puzzles actually get much easier with longer text.
Some things you could do better would be to try and use each letter letter at least twice. In this case "u" "p" and "v" all only occured once, so there's no way I could be 100% sure they were correct. It's okay to have one letter that only appears once, but having things appear just twice (like you did with "y") is better. Also, you should be a little bit more careful about where you're going to put the breaks in the tablet. When they're over letters that are very similar looking (which is also bad, but inevitable), it can be very difficult. In particular, I thought the "s" in "indivisible" was a "v" for most of the time I spent on the puzzle. Finally, you might consider either trying to add punctuation into the tablet in some way (spacing, using more lines, etc), or making the text a little clearer without it, as that was obviously one of the things I found most confusing.
With regards to the actual riddle, that's the part that's hardest to convey to a test group like this, since we don't know the world. You'll want to be sure that you drop hints about things like prime numbers, Atlantis, and the whole Eden thing so that the players know what your referencing in the riddle. You should definetally focus more on giving them background knowledge ahead of time, rather than making the puzzle text too long and explicit. If they get stuck, don't feel bad about letting someone make a very easy knowledge check to give them information and point them in the right direct.
I hope this helps. You've got a great start here. IMO it just needs a couple of very minor tweaks before it's ready to throw at players.