Argus
Argus is the Argus Story-Engine, and is a hand-rolled engine for choice-based interactive-fiction, not dissimilar to visual-novels.
One of the key features of Argus is that rather than the story progressing for a single protagonist character based solely on player-choices, Argus allows for multiple protagonist characters, each with story-defining choices to make during the course of play. The human player only experiences the story from the perspective of one of the protagonist characters at a time.
This does mean that the outcome of the story is never entirely in the hands of the player. Each of the other main characters will be making their own choices based on their own knowledge, opinions and preferences. You could progress through a story the same way many times and experience quite different narratives, depending on the choices other main characters in the story are making.
Likewise, the human player may choose any of the available main characters at the beginning of the story, and progress through the story from that character’s perspective, making choices for them. All of the main characters experience their parts of the storyline simultaneously, and every character’s choices influence the emerging narrative.
Argus does not (well, not at this stage, anyway) support the sort of graphics that you’d expect from most visual novels. Instead, it mostly uses still images for thematic illustration. That may change if more art support comes along, but Argus is currently focused on the mechanics of choice, and a kinetic style of narrative presentation, which can foster a great deal more immediacy than more traditional written-word works.
SNAFU
SNAFU is the prototype story/novel for Argus, and consists of (presently) thirteen main (that is, playable) characters, each with their own story and part in the larger story, plus the usual supporting cast of minor (non-playable) characters. This number may or may not grow as large as eighteen before the work is done.
SNAFU is a story for adults. It contains mature themes, strong language, and tobacco and alcohol use, but contains almost no violence, and no explicit sexual content.
The story is set around a diplomatic incident between two fictional nations (Westfell and Fracia) during a period not dissimilar to Earth during the early years of the 20th Century when technology was still crude, but advancing in rapid leaps. Borderline industrial steampunk, if you like.
The (spoiler-free) diplomatic incident in question is based on a melange of international disputes that have taken place in our own history within the last two centuries, many of which are far more absurd than this particular tale will likely turn out to be.
SNAFU currently consists of a shade over 128,000 words, which is not as impressive as it seems, as those words are divided up between so many characters.
Nevertheless, the project has gotten through a rather weighty selection of prologues and is well on the way to the end of the first chapter, and progress is steady.