For an overview of acceptable and non-acceptable behaviour, please have a read of:

Itch.io's Community Guidelines

But in brief, here are the key points:

1. No flaming, trolling, spamming, or other disruptive behaviour.
2. Do not create posts about sensitive topics that may instigate argument.
3. Harassment of any individual, regardless of if they are a member or not, will not be tolerated.
4. Do not attempt to impersonate any user, or pass yourself off as a moderator/administrator.
5. Do not post unsolicited or bulk advertising/promotion.
6. Do not violate the Terms of Service

I've a few small additions for this forum space:

1. So we can try and keep this all tidy, please post errors, bugs, typos, etc on the Bugs and Typos board. Do not start new discussions.
2. If you want to theorise or speculate, please give any story details spoiler warnings, and don't include them in your titles, so others can be informed before reading more.
3. If you have any feedback on features you would like to see in the game, or thoughts on how things are playing out, please keep you feedback constructive and polite.