Delta Green Onion Game

2025-12-05T21:32:54Z

An application of The OSR Onion

What adventures do I want my game to support?

I believe in Delta Green as a pathway to *SR style play. In OSR Onion terms this could be because of how much Delta Green is driven by scenario design.

I want to create a game to run Delta Green scenarios and campaigns such as God's Teeth and Impossible Landscapes. I also want to run a campaign through the history of the program before getting into the previously mentioned campaigns.

These adventures use Delta Green's sanity mechanic to keep pressue on the players so I need a way to slot that in but preferably without "sanity".

What procedures do I need?

How players choose to use their time inbetween missions is critical. Choosing between their bonds, skills, or the unnatural should be interesting.

Usually the precedure involves making a single choice no matter how much time you have inbetween missions. Does this feel good? I can imagine a player wanting to do more than one thing and having a decent arguement for it if they have a big gap inbetween missions. Definetly needs to be a procedure so it doesn't drag.

Mechanics

Other than some resultion mechanic and some way for players to use their skills, I think the most "novel" idea is wrapping the "sanity" system with the skills and bonds in a mental inventory.

also having "sanity" reflect how you're percieved instead of anything else -> weirdness? What about stabilty / grip?

Also not a huge fan of HP when playing as modern humans. I want wounds maybe even hit locations. Really inspired by this and this at the moment.

What does it mean to be shot? Trying to finish the mission with a crazy wound?

Regarding core resolution mechanic do I want the genre convention d100? Leaning towards yes.

I want skills to be free form / player defined. I also would want my adventures to provide players with a list of the sort of skils the mission requires.

Character

I feel like I have to lock down my choices in the mechanics sectionto fill this out but some quick questions I need to be able to answer:

How many wounds can a character survive with?

How big should the "brainventory" be? I want to fit skills, bonds, and unnatural knowledge in it. Maybe something about the fitting the unnatural in the human brain involves overwriting existing information instead of being able to slot it into empty brain meat.

Is this genre about tracking what tools the agents bring in? I guess it is mission dependant. Open question because I don't find it very rewarding to have a out of fiction resource that you can burn to say that you had the item the whole time but maybe I need to play more of a game that allows that.

Players define their skills and assign percentages to them.