Aye, for GURPS/Champions, as a GM, I always had a cheat sheet of their hunted, quirks, and weaknesses. I strived to apply at least one of them during each session. And, leave the players guessing as to who was 'it'.
[Story time tangent]
I think one of my most favorite times GMing was to see the look on a player's face when they were taking on a minor villain and Dr. Destroyer dropped a couple of his DestroyerBots on the team. (literally...)
<crackle from the built-in speakers> "Accelerator, I heard you were in the neighborhood. I thought you might be bored. Hugs and kisses, Doctor Destroyer." <dramatic pause> "DESTROYERBOTS! DESTROY THEM!"
The other players turned to look at Accelerator's player in disbelief, "You chose Dr. Destroyer as your hunted?"
[OMG, I remember that like it was yesterday. Good times.]