Why Different Rules?

The Brochure Games have a small footprint.
When you are asking a Bookstore that doesn't specialize in RPG's to carry your games, a small foot print helps get you on the shelf!

If a Gamer is in a Bookstore and interested in buying the game, they may want to pick up all three.
All three games needed to be different.
The Buyer wants to feel like they got their money's worth.
One set of rules, "reskinned," feels like you just got ripped off.
Each game needed a different set of rules and a different objective.

The Nightwork is a Solo Journal Game, you don't need other people to play it!
Under the Moonlight should do something different.

Under the Moonlight is the first game that truly embraces Aurora's history...
Aurora really had Grave robbers!
It really was a "Victimless Crime."
"The Soul had left the body, therefore what remains is discarded for any to dispose or use as they will."
(That's a paraphase, not a real quote)
There really was a riot in St. Charles by outraged people in mourning, "You can't dig up our loved ones and get away with it!" 
One of the things like about this game is if you want to introduce magic, the rules don't prevent you from doing that.
You can encounter a zombie, a witch, or whatever.
However,  the game as written is a purely historical and I'm extremely confident that it's historically accurate!!!
Digging up a grave is a problem that doesn't need magic to make it challenging!
You're a Grave Robber!
Own it!
Try to get away with it!
Good luck!