This will complete Ruby Warrior levels 3-7. Won't run on level 1 and 2 because those didn't introduce certain methods yet. Didn't think to save those 2.

ruby_warrior_level_7.rb

class Player
  def initialize
    @direction = :forward
    @keep_retreating = false
  end
  
  def play_turn(warrior)
    @warrior = warrior
    
    if @warrior.feel(@direction).wall?
      flip_direction!
    else
      if almost_dead? || keep_retreating?
        retreat!
      else
        venture_forth!
      end
    end
    @health = @warrior.health
  end
  
  def venture_forth!
    if @warrior.feel(@direction).empty?
      @warrior.walk!(@direction)
    elsif @warrior.feel(@direction).enemy?
      @warrior.attack!(@direction)
    elsif @warrior.feel(@direction).captive?
      @warrior.rescue!(@direction)
    end
  end
  
  def almost_dead?
    @warrior.health < 9
  end
  
  def retreat!
    if @warrior.health < @health then @warrior.walk!(opposite_direction) else @warrior.rest! end
    @keep_retreating = fully_healed? ? false : true
  end
  
  def fully_healed?
    @warrior.health == 20
  end
  
  def keep_retreating?
    @keep_retreating
  end
  
  def opposite_direction
    @direction == :forward ? :backward : :forward
  end
  
  def flip_direction!
    @direction = opposite_direction
    @warrior.pivot!(@direction)
  end
end