Thanks for the feedback!

I originally had rules using 2d6 and resolution similar to PBtA, but I wanted something a little more visceral that gave players something to hang on to, so I went with cards. In a more produced version the cards would be more thematic, with the Aces being fire, the tens being some sort of shadowy monster bone chilling representing "The Dark". The other cards would be stylized books.

 Or something along that line  :)

Most of the time the "fails" would be success with complications, I believe. A "fail forward" approach. And example success with a complication would be if you tried to sneak by a guard, you would succeed but as you close the door quietly behind you there is a soft click and you realize you are on the wrong side of a locked door. Getting back out may not be as easy as getting in...