The rule says 

"Submissions containing depictions of suicide or self-harm will be disqualified and removed.  Text, whether in-game or in the files of the submission, containing instructions, encouragement of, or statement of intent of suicide or self-harm are similarly disqualified."

I'd like to know where the lines are on this, because that takes some stuff off the table with a horror game. 

If the lines are "depiction" (I assume direct depiction or what might be considered immediate indirect depiction), "instructions" "encouragement" and "statement of intent" does this mean that anything that isn't those things is allowed with regard to themes of suicide? Allusion, historical incident, detections of mental states where there is no statement of intent to commit suicide but one might conclude that they're in that state of mind, and less direct stuff like that, for instance? 

Where does the line fall between suicide and murder with regard to horror (PARTICULARLY J-horror - I have a Cure/Pulse double feature planned tonight so this limitation is on my mind) tropes like possession or hypnosis? What about things like willing human sacrifice or any other form of consensual death, which might fall under the definition of something like assisted suicide?

Any other guidelines here? Or is it a blanket ban on depicting any world in which suicide and self-harm provably happen?

If you're concerned about your specific scenario, you're welcome to seek approval for it ahead of time through the itch.io community pages here or through our Discord.  I collect prior approvals for concepts and provide them to the judges explaining the intent.  The reason this rule exists is because we've had issues with the subject matter in the past, how it's been treated by former participants, and issues that have arisen as a result of allowing the content.  To protect the hosts, the volunteers of the competition, the participants, and itch.io staff, this rule has been added and will be maintained for this iteration of the event and likely all future iterations.

To answer your question, I'll walk through the wording to help it be more clear. if you're still uncertain, refer back to prior approvals of concepts at the top here.

- Text, whether in-game or in the files of the submission

This means if it is viewable to the players through regular play of your visual novel, or is observable through examining the files contained therein.  

- Instruction:

In this case, any situation depicted where it would provide the reader knowledge or methodology to conduct their own suicide with the intent of doing so.  e.g: How and where to inflict injury, what substances and implements to use for it, etc.   

This would not include situations where the reader or characters are being informed of the danger of something, say a poisonous mushroom, where the intent is to protect them from harm or warn them.  This also would not include situations where a character is taught how to harm another, say a ghost, in methods that could be applied to the character or reader as the intent is not to educate on self harm or suicide.

This would include both step by step depictions, or self evident depictions of suicide.

An exemption we have made to this involved a murder mystery, where the detective had to determine if a death was a suicide and by what means, with the act or result itself never being fully on screen, and the treatment of suicide to be marked as an unglamorous and unfortunate event.  

- Encouragement

In this case, any situation where it encourages the reader or participants to consider suicide through direct statement or glorification of suicide, but also any situation where characters may encourage others to do so in a direct manner.

This would not include situations where a character may be the subject of bullying, which could result in self-destructive behavior, but would include situations where the bullying directly asserts that the subject of the bullying kill themselves.

Glorification would not include heroic sacrifices, where a character puts themselves into harm's way to save someone else.  The goal and intent is to protect something or someone else, not inflict harm to themselves.

We've yet to make an exception to this particular part of the rule.

- Statement of intent

In this case, if any character or body of text expresses the intent or desire to harm or kill themselves.  This includes ambiguous bodies of text within the game or within the files of the game.

This does not include situations like the murder mystery mentioned above, where a suicide note(fabricated or authentic) was a piece of evidence and the treatment of the suicide is unglamorous and unfortunate.

Specific to your questions:

- Allusion

In most cases, allusion to the fact would be fine.  In film, most of Bill Murray's character in Groundhog Day would be acceptable as it doesn't show the act, but displays situations where death by suicide is the likely outcome.

- Historical incident

There's two ways to read this, so I'm going to answer it as both and hope it satisfies what you need to know:

In the sense that "This is a suicide that happened in this narrative, but is being relayed through a third party outside of the suicide event itself" this would be acceptable in nearly all cases.  As an example, a researcher giving a report of a monster in containment that is known to possess people who interact with it to kill themselves.  As long as other rules above  are maintained, I would suspect there would be no issues with it but would encourage prior approval to be certain.

In the sense that "This is a real event that happened and this is in a non-fiction context," the rule would apply as normal.  The origin of the story, fiction or not, does not change the ruling.

- detections of mental states where there is no statement of intent to commit suicide but one might conclude that they're in that state of mind, and less direct stuff like that, for instance? 

Most of these would be fine, but I would recommend that if you're concerned about it you seek prior approval for your specific scenario.

ah, i just found this. This was helpful for me to see. Sadly it does ruin a lot of horror content. Doki Doki would not be allowed here, nor fnaf, Spooky's House of Jump Scares, Voices of the void, Mandela Catalogue, nana825763, David FIrth, Film Cow, adventure time, Dragon Age Blood Magic or well... pretty much any long form media I can think of. Even MLP had Trixie try to off herself on camera. It also seems to prevent the ability to tell traditional eldritch horror, or stories about recovery after a suicide attempt and learning to find purpose in life again.
for some of us, we've been there. We've been in those darkest of moments and attempted to take our own lives. Horror is a great place for us to express how we felt, to show others through art and to have them understand us a little more. It can be a real good therapeutic method for healing and bonding. 

I was really hoping to hear it would be allowed again next year, but I guess from what I can tell this jam is trying to become increasingly more soft and increasingly less horror focused. 

I am glad to see an explanation and can understand why one would be cautious, there are a few creators, usually edgy teens, or Visual Novels that don't know how to end a story properly that will go overboard. Those are not great. However, the way this rule works for this year's jam is way too strict and a bit silly if I'm being totally honest, a few bad apples does not spoil the bunch. However, even though I respect the decision to go more safe it does mean it will limit some of the creators that have truly personal stories to share.

I do hope that next year they lessen the rule, not saying to remove it entirely, but to make it more open for those of us that have those personal stories to share. Youtube's done enough to damage and condemn horror as a genre already, we need more freedom not less.  Oh well, we'll see what happens.

Glad to see the explanation at least. I couldn't seem to find it anywhere else.

another update on this. I was watching Superman and Louis, a wholesome superhero show about superman and his family. The kid's friend had tried to kill themselves a year before the story starts, and the family is dealing with the fallout and recovery of that. Including therapy, and trying to find purpose again... I guess we can add superman to the list of 'you can't write a story like it for spooktober jam'