If all the players are stuck and no one can play a card or get rid of the enemy in front of you, what do you do? We've just been discarded our hand of cards (using our power but in a useless way) and then drawing more. I couldn't find this explained in the rulebook.
As long as it is not a boss card you can play cards that do not match one of the symbols on the card. This gets you below the starting had size and allows you to draw more cards.
In the retail edition of the game the only place I can find this in the rules is page 7 under Rules For Playing Cards. What is says is "Once you get to the Dungeon Boss, you are not allowed to play Resource Cards that don’t match the boss’ symbols", so as it is specifically called out that you cannot play non-matching cards in a boss fight, then you can play them in a non-boss fight.