We can get a general sense of the "difficulty" of each puzzle by comparing how many incorrect submissions were received with how many correct submissions were received.

Assessing the difficulty of puzzles varies on how difficulty is defined, given that difficult puzzles may have either been a) unapproachable (and therefore received few submissions), or b) deceptive (and therefore received submissions more likely to be incorrect). We have chosen the second definition, given that we have described the popularity of puzzles in the section above, but "difficulty" here should be interpreted in the context of popularity as well. Note this graph differs from the previous graph - this graph tallies total submissions including those from the same participant; the previous graph tallies only the number of participants who submitted at least one solution to each puzzle.

The puzzle with the highest ratio of incorrect to correct submissions was the Meta puzzle Lost in a Library (8 incorrect submissions for every 1 correct submission), though interestingly the puzzle with the highest absolute number of incorrect submissions was the Abstract sample puzzle, Metabolic Mayhem.

Metabolic Mayhem was cast as a sample puzzle as it consisted of the interpretation of an abstract animation, which we believed too ambiguous to be included in the main puzzle hunt (and which appears to have been a correct decision).

This puzzle depicted an abstract animation of a metabolic pathway in a normal and a pathological state. The metabolic pathway consisted of an unknown particle being carried by gradually-diminishing particles through the blood stream before being cleared by receptors from an unknown organ; in the pathological state, these particles accumulated in the bloodstream due to dysfunctional receptors. Participants were asked to determine the gene mutation involved in the pathological state.

Out of interest for this particular puzzle, here were some of the responses received:

The intended correct answer was LDLR; however, it was very interesting to see the wide array of genes people could draw parallels to in the abstract depiction. We are interested in the ways abstract modelling might similarly be able to make different pathways relatable, and while these may not be suitable as puzzles for inclusion into the Puzzle Hunt, we will look for an avenue for these to return.

All game-type puzzles were entirely client-side; we made our best efforts to obscure the answers from the client-side code (including the fact that the code was transpiled from Elm to JavaScript and minified), but these puzzles are not uncrackable. Although, as we are a coding group, we believe it just as valid to have derived the solution from the client-side code as it is from pursuing the "intended" solution path - after all, it is also interesting to think of how to use code to examine the internals of the tools we use and derive useful (but hidden) information.

A number of puzzles had no incorrect submissions, though these had a low number of submissions in total and are therefore hard to interpret. Most of these were game-type puzzles, which divulged the solution after you completed the game - and in such cases, there was no chance of submitting an incorrect solution at all unless participants guessed or attempted to derive the solution from the client-side code.