gistfile1.rb

class Player
  @stairs = false
  @wall = false

  def play_turn(warrior)
    if damaged_from_behind(warrior)
      warrior.shoot!(:backward)
    else
      if first_non_empty(warrior.look) == "enemy"
        warrior.shoot!
      else
        if warrior.feel.enemy?
           warrior.attack!
        elsif warrior.feel.captive?
          warrior.rescue!
        else
          if warrior.health < 20
            injured(warrior)
          else
            explore(warrior)
          end
        end
      end
    end
    @health = warrior.health
  end
  
  def can_fight?(warrior)
    warrior.health > 15
  end
  
  def taking_damage?(warrior)
    warrior.health < @health
  end
  
  def injured(warrior)
    if taking_damage?(warrior)
      if can_fight?(warrior)
        warrior.walk!
      else
        warrior.walk!(:backward)
      end
    else
      warrior.rest!
    end
  end
  
  def explore(warrior)
    if warrior.feel.stairs?
      @stairs = true
      if @wall
        warrior.walk!
      else
        warrior.pivot!
      end
    elsif warrior.feel.wall?
      @wall = true
      warrior.pivot!
    else
      warrior.walk!
    end
  end
  
  def first_non_empty(spaces)
    first_non_empty = "blank"
    spaces.each do |space|
      if space.enemy?
        return "enemy"
      elsif space.captive?
        return "captive"
      end
    end
    return first_non_empty
  end
  
  def damaged_from_behind(warrior)
    warrior.health < 20 && taking_damage?(warrior) && first_non_empty(warrior.look(:backward)) == "enemy"
  end
  
end

I'm not sure if it's possible in the game or not, but I'd probably add an initializer for this class and set the warrior to an instance variable and then you don't have to pass it around to all the different methods. I.E.

def initializer(warrior)
  @warrior = warrior
end

Then you can just use @warrior in all your methods instead of passing it around a bunch.

I would probably write the first_non_empty method as:

def first_non_empty(spaces)
  spaces.each do |space|
    return "enemy" if space.enemy?
    return "captive" if space.captive?
  end
  "blank"
end

I don't see in here if you're doing anything with the @stairs instance var other than setting it. Maybe that comes later?

The main other thing I'd note is usually when I write something that ends up with a bunch of if, else, elsif blocks in it I usually try to go back and refactor it into some smaller methods. Like in the play_turn method I could see having helper methods you could call for should_shoot, should_attack, and check_health each of which would only have a single if statement. Not a big deal but might make for a little cleaner code.

I use the @stairs and @Wall instance variables to make sure I've explored all spaces so there is no captive remaining.

I've updated the code: https://gist.github.com/nicusg/6290804