Rewritten some methods

warrior.rb

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

    check_health
  end
  
  def should_look
    if first_non_empty(@warrior.look) == "enemy"
      @warrior.shoot!
    else
      should_move
    end
  end
  
end

Nice, that looks better.