Demon City's Downtime system is basically a re-tool of Jeff's Party Like It's 999.
The money system is basically from FASERIP
Contacts are a combo of FASERIP's Jeff Grubb's Genius Subplot Rule and the way they work in Night's Black Agents.
Combat is 5e's advantage/disadvantage on steroids. I think Jeff may have suggested something along one of these lines once.
The Tarot thing are relatively out of nowhere I think.
Motives instead of classes is more like Vampire than anything else I can think of that I read, but still pretty much out of nowhere.
Calm is obviously like Call of Cthulhu Sanity and probably nobody would want it any other way, though I hope Downtime puts a new spin on it.
Most of the feedback has been too good to be useful. Just a lot of "I like the__! and the__!" which is nice but the sample is kind of self-selected--they're backing it so they're getting what they want. If anybody reading has anything they just thought of, hit me with it.
I'm curious about how long-term play will work. In sunday's D&D game, we thought Agnes Steelheart was just fucking dead the other day until shenanigans restored her and it was clear it hurt. I want to figure out if the stack of rewards and interrelationships Demon City creates will eventually make that happen with a PC that's around long enough, or if you just basically have to choose between horror and that level of attachment.