Just wondering; I have yet to receive one, I have checked all spam folders and confirmed that my email listed with itch.io is correct.
Have steam keys been sent out yet?
Yes, Steam keys are available! As far as I know, I can't email them out. Instead, you can claim your key from your unique download page (linked at the top of the page here: https://minorkeygames.itch.io/slayer-shock). More details: https://itch.io/docs/buying/already-bought