Metapuzzle

Metapuzzles (often shortened to metas) are a unique type of puzzle, in that they cannot be solved as standalone puzzles. Metapuzzles require the use of information from other puzzles to be solved. This information is usually in the form of those puzzles' answers (usually called feeder puzzles or feeders), but can also extend to knowing how the puzzles were solved. It's rare for a hunt to not have any metapuzzles as they act as a good way to wrap up individual rounds; as long as a hunt has puzzles that can be organized into at least one round (or round-like set), a metapuzzle can provide a conclusion to both the puzzle content and whatever story elements are in play.

Puzzle Application
Metapuzzles can come in a few distinctive forms, ranging from minimalist to positively crowded.

Pure Meta
A "pure" meta is one end of the meta spectrum, following the principle of "less is more". Pure metas provide little to no information for solvers to use when approaching them. Usually, the maximum allowable information is a title (something most puzzles will have anyway), puzzle ordering, and flavortext. Whether the flavortext is actually helpful is up to the metapuzzle writer. In some cases, a pure meta may contain a list of what puzzles go to it, but this is usually reserved for hunts that utilize meta-matching.

Pure metas can often work quite well with meta-matching as a mechanic; assuming that there's only one complete configuration of answer-to-meta assignment, having pure metas can remove a lot of work from the writer (if they're good at writing pure metas, that is). However, it does still require a lot of foresight from the author, as they have to be sure that it's clear either while or after solving a particular pure meta which of the metas solvers should submit for.

Shell Meta
The antithesis to pure metas, shell metas take up the rest of the aforementioned meta spectrum. A shell meta has very little constraint in what information can be presented, as long as there is some way to input feeders. This can range from series of blanks to fill in with the answers to a system for transforming them to an amount of content that could easily be confused with a regular feeder puzzle, if not for being unsolvable without the feeder answers.

Shell metas are a lot more common than pure metas, as finding sets of words or phrases that can be extracted from with minimal extra involvement is a very difficult process. Having an extra step to funnel the answers through can alleviate some degree of weight placed on the answer selection itself.

Mini-Meta
While not a type of meta that falls anywhere in particular on the minimum/maximum scale, mini-metas are still worth bringing up. Unlike regular metas, mini-metas are actually a type of feeder puzzle. Instead of requiring other feeder puzzle answers to be solved, they are usually accompanied by a series of mini-puzzles. These mini-puzzles individually take less time to solve than other full puzzles in the hunt, and each contribute an answer to the mini-meta. Then, the mini-meta results in a new feeder answer for whatever that round's meta is. It's meta-ception!

Revisitation Meta
Instead of using puzzle answers as part of the meta, revisitation metas exclusively use the content or solve path of a particular puzzle. Commonly used in the REDDot Puzzle Hunt, this type of meta can act as a kind of gating mechanism, confirming that solvers understand how a particular puzzle is solved. Commonly, they'll involve extracting a single letter in the same method as the original puzzle, but they can also involve just recognizing snapshots of certain puzzles, or going back to puzzles to solve them in a different way. Whatever form they take, revisitation metas are unique in how they break the usual conventions of metapuzzles.

Token Meta
Instead of directly using puzzle answers as part of the meta, solving a puzzle instead gives another piece of information (usually another answer-like string, but this can take on different forms, such as minipuzzles in the CiSRA Puzzle Competition) that is used for the meta instead. This is generally done to make hunt construction easier, as authors are no longer constrained to having to write puzzles that solve to a specified answer.

Mini-Metas

 * Courthouse (MITMH 2020)
 * Peak Adventure (MITMH 2020)