diff --git a/assets/ambient_1.ogg b/assets/ambient_1.ogg
new file mode 100644
index 0000000..55b2bdb
Binary files /dev/null and b/assets/ambient_1.ogg differ
diff --git a/assets/config.json b/assets/config.json
index 0f35f0b..00cd639 100644
--- a/assets/config.json
+++ b/assets/config.json
@@ -5,7 +5,8 @@
     "monster_1": "assets/monster-1.ogg",
     "walk": "assets/blank.ogg",
     "blank": "assets/blank.ogg",
-    "pickup": "assets/pickup.ogg"
+    "pickup": "assets/pickup.ogg",
+    "ambient_1": "assets/ambient_1.ogg"
   },
   "sprites": {
     "armored_knight": "assets/armored_knight_1-256.png",
diff --git a/boss_fight_ui.cpp b/boss_fight_ui.cpp
index 2a924de..1b746f7 100644
--- a/boss_fight_ui.cpp
+++ b/boss_fight_ui.cpp
@@ -2,20 +2,22 @@
 #include "easings.hpp"
 
 namespace gui {
-  BossFightUI::BossFightUI() {
+  BossFightUI::BossFightUI(GameLevel level)
+    : $level(level)
+  {
     $status.position(0, 0, 300, SCREEN_HEIGHT);
     $status.layout(
-        "[(150)status_1|(150)status_2]"
+        "[main_status]"
         "[(150)status_3|(150)status_4]"
         "[(150)status_5|(150)status_6]"
         "[(150)status_7|(150)status_8]"
         );
 
     $overlay.position(300, 0, SCREEN_WIDTH - 300, SCREEN_HEIGHT);
-    $overlay.layout("[overlay_1|overlay_2|overlay_3|overlay_4]"
-    "[overlay_5|overlay_6|overlay_7|overlay_8]"
-    "[overlay_9|overlay_10|overlay_11|overlay_12]"
-    "[overlay_13|overlay_14|overlay_15|overlay_16]");
+    $overlay.layout("[overlay_1|overlay_2|overlay_4]"
+    "[overlay_5|overlay_6|overlay_8]"
+    "[overlay_9|overlay_10|overlay_12]"
+    "[overlay_13|overlay_14|overlay_16]");
 
     $boss_image = textures::get("boss_fight");
     auto bounds = $boss_image.sprite->getLocalBounds();
@@ -32,7 +34,11 @@ namespace gui {
       $status.set<Clickable>(button, {
           [this, name](auto, auto){ fmt::println("STATUS: {}", name); }
       });
-      $status.set<Label>(button, {name});
+      if(name == "main_status") {
+        $status.set<Textual>(button, {fmt::format("HP: {}", $boss_hp)});
+      } else {
+        $status.set<Label>(button, {"Attack"});
+      }
     }
     $status.init();
 
@@ -43,15 +49,13 @@ namespace gui {
       });
     }
 
-    auto region = $overlay.entity("overlay_2");
-    $overlay.set<Label>(region, {"THE RAT KING!"});
     $overlay.init();
   }
 
   void BossFightUI::bounce_boss(sf::RenderWindow& window) {
     auto time = $clock.getElapsedTime();
-    float tick = ease::in_out_back(ease::sine(time.asSeconds()));
-    float scale = std::lerp(1.1, 1.3, tick);
+    float tick = ease::out_bounce(ease::sine(time.asSeconds()));
+    float scale = std::lerp(1.0, 1.15, tick);
     $boss_image.sprite->setScale({scale, scale});
     window.draw(*$boss_image.sprite);
   }
@@ -63,6 +67,11 @@ namespace gui {
       window.draw(*$boss_image.sprite);
     }
 
+    if($boss_hp == 0) {
+      $overlay.show_label("overlay_1", "YOU WON!");
+      $overlay.show_label("overlay_4", "CLICK TO CONTINUE...");
+    }
+
     $status.render(window);
     $overlay.render(window);
   }
@@ -73,10 +82,19 @@ namespace gui {
     }
 
     if($overlay.mouse(x, y)) {
-      fmt::println("OVERLAY");
       $boss_hit = !$boss_hit;
+      $boss_hp--;
     }
 
     return false;
   }
+
+  void BossFightUI::update_level(GameLevel &level) {
+    $level = level;
+    $boss_hp = 10 * $level.index + 1;  // make him stronger
+    $boss_hit = false;
+    $overlay.close<Label>("overlay_1");
+    $overlay.close<Label>("overlay_4");
+    init();
+  }
 }
diff --git a/boss_fight_ui.hpp b/boss_fight_ui.hpp
index 446edf4..ed28550 100644
--- a/boss_fight_ui.hpp
+++ b/boss_fight_ui.hpp
@@ -19,16 +19,20 @@ namespace gui {
   class BossFightUI {
     public:
       sf::Clock $clock;
+      int $boss_hp = 10;
       bool $boss_hit = false;
+      GameLevel $level;
       guecs::UI $status;
       guecs::UI $overlay;
       textures::SpriteTexture $boss_image;
 
-      BossFightUI();
+      BossFightUI(GameLevel level);
 
       void init();
       void render(sf::RenderWindow& window);
       bool mouse(float x, float y);
       void bounce_boss(sf::RenderWindow& window);
+      bool boss_dead() { return $boss_hp < 0; }
+      void update_level(GameLevel& level);
   };
 }
diff --git a/guecs.cpp b/guecs.cpp
index 61cb7b8..47ec57b 100644
--- a/guecs.cpp
+++ b/guecs.cpp
@@ -118,10 +118,50 @@ namespace guecs {
     return action_count > 0;
   }
 
+  void UI::show_sprite(string region, string sprite_name) {
+    auto ent = entity(region);
+
+    if(!has<Sprite>(ent)) {
+      Sprite to_show{sprite_name};
+      auto& cell = cell_for(ent);
+      to_show.init(cell);
+      set<guecs::Sprite>(ent, to_show);
+    }
+  }
+
+  void UI::show_text(string region, string content) {
+    auto ent = entity(region);
+
+    if(auto text = get_if<Textual>(ent)) {
+      text->text->setString(content);
+    } else {
+      auto &cell = cell_for(ent);
+      Textual to_set{content, 20};
+      to_set.init(cell, $font);
+      to_set.text->setFillColor(ColorValue::LIGHT_MID);
+      set<Textual>(ent, to_set);
+    }
+  }
+
+  void UI::show_label(string region, string content) {
+    auto ent = entity(region);
+
+    if(auto text = get_if<Label>(ent)) {
+      text->text->setString(content);
+    } else {
+      auto &cell = cell_for(ent);
+      Label to_set{content, 20};
+      to_set.init(cell, $font);
+      to_set.text->setFillColor(ColorValue::LIGHT_MID);
+      set<Label>(ent, to_set);
+    }
+  }
+
   Clickable make_action(DinkyECS::World& target, Events::GUI event) {
     return {[&, event](auto ent, auto data){
       // remember that ent is passed in from the UI::mouse handler
       target.send<Events::GUI>(event, ent, data);
     }};
   }
+
 }
diff --git a/guecs.hpp b/guecs.hpp
index d39e9fe..52bdb45 100644
--- a/guecs.hpp
+++ b/guecs.hpp
@@ -194,6 +194,18 @@ namespace guecs {
         void remove(DinkyECS::Entity ent) {
           $world.remove<Comp>(ent);
         }
+
+      template <typename Comp>
+      void close(string region) {
+        auto ent = entity(region);
+        remove<Comp>(ent);
+      }
+
+      void show_sprite(string region, string sprite_name);
+      void show_text(string region, string content);
+      void update_text(string region, string content);
+      void update_label(string region, string content);
+      void show_label(string region, string content);
   };
 
   Clickable make_action(DinkyECS::World& target, Events::GUI event);
diff --git a/gui_fsm.cpp b/gui_fsm.cpp
index 552bf77..3b00990 100644
--- a/gui_fsm.cpp
+++ b/gui_fsm.cpp
@@ -20,6 +20,7 @@ namespace gui {
     $map_ui($level),
     $combat_ui($level),
     $status_ui($level),
+    $boss_fight_ui($level),
     $font{FONT_FILE_NAME}
     {
     }
@@ -246,6 +247,10 @@ namespace gui {
           sf::Vector2f pos = $window.mapPixelToCoords(mouse->position);
           if(in_state(State::NEXT_LEVEL)) {
             $boss_fight_ui.mouse(pos.x, pos.y);
+
+            if($boss_fight_ui.boss_dead()) {
+              event(Event::STAIRS_DOWN);
+            }
           } else {
             $combat_ui.$gui.mouse(pos.x, pos.y);
             $status_ui.$gui.mouse(pos.x, pos.y);
@@ -415,6 +420,7 @@ namespace gui {
     $combat_ui.update_level($level);
     $map_ui.update_level($level);
     $main_ui.update_level($level);
+    $boss_fight_ui.update_level($level);
 
     run_systems();
   }
diff --git a/main.cpp b/main.cpp
index 9dccd6d..d5aa686 100644
--- a/main.cpp
+++ b/main.cpp
@@ -6,11 +6,13 @@
 int main(int argc, char* argv[]) {
   textures::init();
   sound::init();
-  sound::mute(true);
+  sound::mute(false);
   gui::FSM main;
   main.event(gui::Event::STARTED);
   Autowalker walker(main);
 
+  sound::play("ambient_1", true);
+
   if(argc > 1 && argv[1][0] == 't') {
     walker.start_autowalk();
   }
diff --git a/main_ui.cpp b/main_ui.cpp
index a48bad7..2655925 100644
--- a/main_ui.cpp
+++ b/main_ui.cpp
@@ -55,7 +55,7 @@ namespace gui {
         $rayview.$dir_x, $rayview.$dir_y,
         VSYNC, FRAME_LIMIT, DEBUG_BUILD);
 
-    $overlay_ui.update_text("top_left", stats);
+    $overlay_ui.show_text("top_left", stats);
   }
 
   void MainUI::draw_blood() {
@@ -115,7 +115,7 @@ namespace gui {
     auto debug = $level.world->get_the<Debug>();
     if(debug.FPS) draw_stats();
 
-    draw_blood();
+    // draw_blood();
   }
 
   bool MainUI::play_rotate() {
@@ -140,7 +140,7 @@ namespace gui {
   void MainUI::plan_rotate(int dir) {
     // -1 is left, 1 is right
     $compass_dir = ($compass_dir + dir) % $compass.size();
-    $overlay_ui.update_label("top", $compass[$compass_dir]);
+    $overlay_ui.show_label("top", $compass[$compass_dir]);
     $camera.plan_rotate($rayview, dir);
   }
 
@@ -166,7 +166,7 @@ namespace gui {
     $rayview.position_camera(player.x + 0.5, player.y + 0.5);
 
     $compass_dir = 0;
-    $overlay_ui.update_label("top", $compass[$compass_dir]);
+    $overlay_ui.show_label("top", $compass[$compass_dir]);
     dirty();
   }
 
diff --git a/overlay_ui.cpp b/overlay_ui.cpp
index e394283..0235d6c 100644
--- a/overlay_ui.cpp
+++ b/overlay_ui.cpp
@@ -28,57 +28,26 @@ namespace gui {
   }
 
   void OverlayUI::show_sprite(string region, string sprite_name) {
-    auto ent = $gui.entity(region);
-    Sprite blood{sprite_name};
-    auto& cell = $gui.cell_for(ent);
-    blood.init(cell);
-    $gui.set<guecs::Sprite>(ent, blood);
+    $gui.show_sprite(region, sprite_name);
   }
 
   void OverlayUI::close_sprite(string region) {
-    auto ent = $gui.entity(region);
-    $gui.remove<guecs::Sprite>(ent);
+    $gui.close<Sprite>(region);
   }
 
   void OverlayUI::show_text(string region, string content) {
-    auto ent = $gui.entity(region);
-    auto &cell = $gui.cell_for(ent);
-    Textual text{content, 20};
-    text.init(cell, $gui.$font);
-    text.text->setFillColor(ColorValue::LIGHT_MID);
-    $gui.set<Textual>(ent, text);
-  }
-
-  void OverlayUI::update_text(string region, string content) {
-    auto ent = $gui.entity(region);
-    if(auto text = $gui.get_if<Textual>(ent)) {
-      text->text->setString(content);
-    }
-  }
-
-  void OverlayUI::update_label(string region, string content) {
-    auto ent = $gui.entity(region);
-    if(auto text = $gui.get_if<Label>(ent)) {
-      text->text->setString(content);
-    }
+    $gui.show_text(region, content);
   }
 
   void OverlayUI::close_text(string region) {
-    auto ent = $gui.entity(region);
-    $gui.remove<Textual>(ent);
+    $gui.close<Textual>(region);
   }
 
   void OverlayUI::show_label(string region, string content) {
-    auto ent = $gui.entity(region);
-    auto &cell = $gui.cell_for(ent);
-    Label text{content, 20};
-    text.init(cell, $gui.$font);
-    text.text->setFillColor(ColorValue::LIGHT_MID);
-    $gui.set<Label>(ent, text);
+    $gui.show_label(region, content);
   }
 
   void OverlayUI::close_label(string region) {
-    auto ent = $gui.entity(region);
-    $gui.remove<Label>(ent);
+    $gui.close<Label>(region);
   }
 }
diff --git a/sound.cpp b/sound.cpp
index 185e306..141369e 100644
--- a/sound.cpp
+++ b/sound.cpp
@@ -37,13 +37,14 @@ namespace sound {
     SMGR.sounds.try_emplace(name, buffer, sound);
   }
 
-  void play(const std::string name) {
+  void play(const std::string name, bool loop) {
     dbc::check(initialized, "You need to call sound::init() first");
     if(muted) return;
 
     if(SMGR.sounds.contains(name)) {
       // get the sound from the sound map
       auto pair = SMGR.sounds.at(name);
+      pair.sound->setLooping(loop);
       // play it
       pair.sound->play();
     } else {
diff --git a/sound.hpp b/sound.hpp
index a20727a..3f3bd98 100644
--- a/sound.hpp
+++ b/sound.hpp
@@ -17,7 +17,7 @@ namespace sound {
 
   void init();
   void load(const std::string name, const std::string path);
-  void play(const std::string name);
+  void play(const std::string name, bool loop=false);
   void play_at(const std::string name, float x, float y, float z);
   void mute(bool setting);
 }