Adventure Games were one of the earliest types of computer games starting with Colossal Cave Adventure in 1976, the game from which the entire genre gets its name. Since then the genre of adventure games has seen a lot of changes from adding graphics in the 80's, its enormous boom in the 90's, exaggerated rumors of its death in the 2000's, and subsequent resurgence largely due to indie game developers.
Throughout all that time, several different types of adventure games can be identified. As you are considering your game for this jam, it may be helpful to familiarize yourself with the various types of adventure games there are.
Text Adventure & Text Parser Graphical Adventure:
These types of adventure games were very popular throughout the 1980's. I'm lumping them together here because a) pure text adventures aren't part of this jam so don't need their own section and b) they play in much the same way. The big difference between them, of course, is that text adventures describe what is going on in text while graphical adventures show it on the screen, and allow you to move the character directly rather than typing directions like "go north" or "go in door."
These games defined what we now mean by an "adventure game." They are intensely story focused and require the player to solve puzzles in order to progress through the story. Mechanics include collecting items and putting them in an inventory. Then those items are used in the world to accomplish goals. All commands are typed as text like "get key" and "open door with key."
Because commands are being entered by the user as text, and almost anything can be expressed in language, the types of puzzles and interactions possible in these games is potentially limitless. This makes the gameplay far more flexible and variant than the later point & click adventures. It has a significant downside, however, in that the developers have to anticipate anything the users might reasonably type in a situation including all synonyms they might use. This results in players tending to see a lot of "I don't understand that, please restate" or something like that after typing a command.
Well known graphical text parser adventures include the original King's Quest, Space Quest, and Leisure Suit Larry games. A contemporary example is the upcoming game Cascade Quest by Icefall Games (to be released in 2018).
Point & Click Adventure:
In the 1990's adventure games turned to a point & click interface, and this is still the standard for adventure games today. Rather than typing commands, the player chooses from a few interactions (or inventory items) and simply clicks the object they wish to interact with. Because of the more limited nature of puzzles one could do this way, most point and click puzzles tend to be a matter of collecting the right inventory items and then using them in the right places.
Early point & click adventures often tried to make the game more challenging by hiding items or objects in the scene resulting in the need to meticulously pixel hunt every scene to find what you need, or developed puzzles that were completely absurd in order to make them non-obvious. More recent games, however, have matured from that and have found better ways to keep the game challenging while not making it tedious.
Point & click adventures tend to have even more complex and engaging stories, and more interesting fleshed-out characters. Thus dialog trees (sometimes quite complex ones) are common in point & click adventures, allowing the NPCs to come alive. Well-designed point & click adventures are known for integrating the puzzles tightly into the narrative rather than just being arbitrary obstacles to progression.
Well known point & click adventures include the later games in the King's Quest and Space Quest series, Day of The Tentacle, and Grim Fandango. Contemporary examples are numerous and include Paradigm, Bear With Me, and any game published by Wadjet Eye Games.
Puzzle Adventure:
Puzzle adventure games are the only type in which the story takes more of a back seat. It's still a story (else it wouldn't be an adventure game!) but the puzzles themselves are front and center. In a puzzle adventure game, the solutions to the puzzles are largely disconnected from the story except in some arbitrary way. For this reason, the story often includes an antagonist who designed the puzzles that the player must now solve. In actuality, the true antagonist in a puzzle adventure is the puzzles.
The puzzles in this type of game are usually a series of stand-alone logic puzzles and tend to be much more difficult than the puzzles in other types of adventure games. This type of game rarely has NPCs, at least of the type you can interact with.
Well known puzzle adventures include Myst and The 7th Guest.
Interactive Visual Novel (or the "choose your own adventure" game):
These games are kind of the opposite of the puzzle adventure. They contain few or no puzzles and instead focus completely on the story and the choices the player makes. Most of these games are dialog-focused with the great majority of choices the player makes being what to say or how to react to another character, and usually a few big decisions at key points in the game.
More than with the previous types, it is imperative in these games that player choices have a real outcome on the story itself, often featuring not only multiple endings, but multiple distinct paths through the story depending on player choice, and thus the player must be presented with meaningful choices throughout the game that profoundly affect the story.
Well known interactive visual novels are Life is Strange and any Telltale game made since 2012 (before 2012 Telltale made point & click adventures)
Walking Simulators:
I personally consider these more of a spin-off of the adventure game genre, but they are clearly related, and acceptable for this jam. The defining characteristic of this type is that there isn't much the player can do except walk around and examine things. There tend to be no NPCs to interact with, either no puzzles at all or a few trivially simple puzzles, and no meaningful choices by the player. These games are all about experiencing the environment and the story passively. Often this is because the story happened in the past, and the player character wasn't a part of it. The player simply finds clues as to what the story was as they progress through the world.
Well known walking simulators include Dear Esther, Gone Home, and The Stanley Parable.
Conclusion
Those are the primary types of adventure games that were and are being made. Have I forgotten any type? If so please let me know!
I'll try to write more posts as the jam draws ever-closer.