I stopped playing for a couple of months but just picked this game up again and it looks like something's changed --- sometimes I am unable to play another card for a particular character until I end the turn again. It used to be that I could play as many cards on one character as I had in my hand --- what's changed?
Nothing like that's changed. Maybe you were under effect of Taunt, or Brains! or other cards with effects that would cause similar situations. What adventure did you last experience this in? Pay attention to any attachments on your character, and we might be able to figure out if there's a logical reason for it.
Other than Taunt or any card with Stun, perhaps it was a Halt effect, like from Hit The Deck or Entangling Roots?
