diff --git a/src/components/three/AnimatedModel.tsx b/src/components/three/AnimatedModel.tsx
index f9c5991..099f14c 100644
--- a/src/components/three/AnimatedModel.tsx
+++ b/src/components/three/AnimatedModel.tsx
@@ -151,7 +151,7 @@ export function AnimatedModel({
       defaultAction.play();
       // eslint-disable-next-line react-hooks/set-state-in-effect
       setIsReady(true);
-      // eslint-disable-next-line react-hooks/set-state-in-effect
+
       setCurrentAnim(defaultAction.getClip().name);
       onLoaded?.();
     } else {
diff --git a/src/components/ui/GameStateHUD.tsx b/src/components/ui/GameStateHUD.tsx
new file mode 100644
index 0000000..eec8a3d
--- /dev/null
+++ b/src/components/ui/GameStateHUD.tsx
@@ -0,0 +1,70 @@
+import { Debug } from "@/utils/debug/Debug";
+import {
+  type MainGameState,
+  useGameStore,
+} from "@/managers/stores/useGameStore";
+
+const MAIN_STATES: MainGameState[] = [
+  "intro",
+  "bike",
+  "pylone",
+  "ferme",
+  "outro",
+];
+
+export function GameStateHUD(): React.JSX.Element | null {
+  const debug = Debug.getInstance();
+  const mainState = useGameStore((state) => state.mainState);
+  const detail = useGameStore((state) => {
+    switch (state.mainState) {
+      case "intro":
+        return state.intro.hasCompleted ? "completed" : "waiting";
+      case "bike":
+        return state.bike.currentStep;
+      case "pylone":
+        return state.pylone.currentStep;
+      case "ferme":
+        return state.ferme.currentStep;
+      case "outro":
+        return state.outro.hasStarted ? "started" : "waiting";
+    }
+  });
+  const setMainState = useGameStore((state) => state.setMainState);
+  const advanceGameState = useGameStore((state) => state.advanceGameState);
+  const resetGame = useGameStore((state) => state.resetGame);
+
+  if (!debug.active) return null;
+
+  return (
+    <aside className="game-state-hud" aria-label="Game state debug panel">
+      <div className="game-state-hud__header">
+        <span>Game State</span>
+        <strong>{mainState}</strong>
+      </div>
+
+      <p className="game-state-hud__detail">Sub state: {detail}</p>
+
+      <div className="game-state-hud__states" aria-label="Main states">
+        {MAIN_STATES.map((state) => (
+          <button
+            key={state}
+            className={state === mainState ? "is-active" : undefined}
+            type="button"
+            onClick={() => setMainState(state)}
+          >
+            {state}
+          </button>
+        ))}
+      </div>
+
+      <div className="game-state-hud__actions">
+        <button type="button" onClick={advanceGameState}>
+          Next step
+        </button>
+        <button type="button" onClick={resetGame}>
+          Reset
+        </button>
+      </div>
+    </aside>
+  );
+}
diff --git a/src/index.css b/src/index.css
index a32c152..763ef06 100644
--- a/src/index.css
+++ b/src/index.css
@@ -391,6 +391,77 @@ canvas {
   letter-spacing: 0.03em;
 }
 
+.game-state-hud {
+  position: fixed;
+  top: 18px;
+  right: 18px;
+  z-index: 20;
+  display: grid;
+  gap: 12px;
+  width: min(320px, calc(100vw - 36px));
+  padding: 14px;
+  border: 1px solid rgba(255, 255, 255, 0.18);
+  border-radius: 18px;
+  background: rgba(4, 7, 13, 0.78);
+  box-shadow: 0 18px 60px rgba(0, 0, 0, 0.35);
+  color: #f8fafc;
+  backdrop-filter: blur(16px);
+}
+
+.game-state-hud__header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+}
+
+.game-state-hud__header span,
+.game-state-hud__detail {
+  color: rgba(248, 250, 252, 0.68);
+  font-size: 12px;
+  font-weight: 700;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+}
+
+.game-state-hud__header strong {
+  font-size: 16px;
+  letter-spacing: -0.03em;
+  text-transform: uppercase;
+}
+
+.game-state-hud__detail {
+  margin: 0;
+  text-transform: none;
+}
+
+.game-state-hud__states,
+.game-state-hud__actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+
+.game-state-hud button {
+  min-height: 32px;
+  padding: 0 10px;
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  border-radius: 999px;
+  background: rgba(255, 255, 255, 0.08);
+  color: #f8fafc;
+  font-size: 12px;
+  font-weight: 700;
+  cursor: pointer;
+}
+
+.game-state-hud button:hover,
+.game-state-hud button:focus-visible,
+.game-state-hud button.is-active {
+  border-color: rgba(125, 211, 252, 0.75);
+  background: rgba(125, 211, 252, 0.18);
+  outline: none;
+}
+
 /* Editor page */
 .editor-container {
   position: fixed;
diff --git a/src/managers/stores/useGameStore.ts b/src/managers/stores/useGameStore.ts
index 6d0e8fd..78e683e 100644
--- a/src/managers/stores/useGameStore.ts
+++ b/src/managers/stores/useGameStore.ts
@@ -1,7 +1,14 @@
 import { create } from "zustand";
 
 export type MainGameState = "intro" | "bike" | "pylone" | "ferme" | "outro";
-export type MissionStep = "locked" | "inspect" | "repair" | "done";
+export type MissionStep =
+  | "locked"
+  | "waiting"
+  | "inspected"
+  | "fragmented"
+  | "scanning"
+  | "repairing"
+  | "done";
 
 export interface IntroState {
   dialogueAudio: string | null;
@@ -39,31 +46,54 @@ interface GameActions {
   setPyloneState: (pylone: Partial<GameState["pylone"]>) => void;
   setFermeState: (ferme: Partial<GameState["ferme"]>) => void;
   setOutroState: (outro: Partial<GameState["outro"]>) => void;
+  completeIntro: () => void;
+  completeBike: () => void;
+  completePylone: () => void;
+  completeFerme: () => void;
+  startOutro: () => void;
+  advanceGameState: () => void;
   resetGame: () => void;
 }
 
 export type GameStore = GameState & GameActions;
 
+function getNextMissionStep(step: MissionStep): MissionStep {
+  switch (step) {
+    case "locked":
+    case "waiting":
+      return "inspected";
+    case "inspected":
+      return "fragmented";
+    case "fragmented":
+      return "scanning";
+    case "scanning":
+      return "repairing";
+    case "repairing":
+    case "done":
+      return "done";
+  }
+}
+
 function createInitialGameState(): GameState {
   return {
     mainState: "intro",
     intro: {
-      dialogueAudio: ""null,
+      dialogueAudio: null,
       hasCompleted: false,
       isBikeUnlocked: false,
     },
     bike: {
-      currentStep: "locked",
+      currentStep: "waiting",
       dialogueAudio: null,
       isRepaired: false,
     },
     pylone: {
-      currentStep: "locked",
+      currentStep: "waiting",
       dialogueAudio: null,
       isPowered: false,
     },
     ferme: {
-      currentStep: "locked",
+      currentStep: "waiting",
       dialogueAudio: null,
       irrigationFixed: false,
     },
@@ -87,5 +117,149 @@ export const useGameStore = create<GameStore>()((set) => ({
     set((state) => ({ ferme: { ...state.ferme, ...ferme } })),
   setOutroState: (outro) =>
     set((state) => ({ outro: { ...state.outro, ...outro } })),
+  completeIntro: () =>
+    set((state) => ({
+      mainState: "bike",
+      intro: {
+        ...state.intro,
+        hasCompleted: true,
+        isBikeUnlocked: true,
+      },
+      bike: {
+        ...state.bike,
+        currentStep: "inspected",
+      },
+    })),
+  completeBike: () =>
+    set((state) => ({
+      mainState: "pylone",
+      bike: {
+        ...state.bike,
+        currentStep: "done",
+        isRepaired: true,
+      },
+      pylone: {
+        ...state.pylone,
+        currentStep: "inspected",
+      },
+    })),
+  completePylone: () =>
+    set((state) => ({
+      mainState: "ferme",
+      pylone: {
+        ...state.pylone,
+        currentStep: "done",
+        isPowered: true,
+      },
+      ferme: {
+        ...state.ferme,
+        currentStep: "inspected",
+      },
+    })),
+  completeFerme: () =>
+    set((state) => ({
+      mainState: "outro",
+      ferme: {
+        ...state.ferme,
+        currentStep: "done",
+        irrigationFixed: true,
+      },
+      outro: {
+        ...state.outro,
+        hasStarted: true,
+      },
+    })),
+  startOutro: () =>
+    set((state) => ({
+      mainState: "outro",
+      outro: {
+        ...state.outro,
+        hasStarted: true,
+      },
+    })),
+  advanceGameState: () =>
+    set((state) => {
+      if (state.mainState === "intro") {
+        return {
+          mainState: "bike",
+          intro: {
+            ...state.intro,
+            hasCompleted: true,
+            isBikeUnlocked: true,
+          },
+          bike: {
+            ...state.bike,
+            currentStep: "inspected",
+          },
+        };
+      }
+
+      if (state.mainState === "bike") {
+        const nextStep = getNextMissionStep(state.bike.currentStep);
+        if (nextStep === "done") {
+          return {
+            mainState: "pylone",
+            bike: {
+              ...state.bike,
+              currentStep: "done",
+              isRepaired: true,
+            },
+            pylone: {
+              ...state.pylone,
+              currentStep: "inspected",
+            },
+          };
+        }
+
+        return { bike: { ...state.bike, currentStep: nextStep } };
+      }
+
+      if (state.mainState === "pylone") {
+        const nextStep = getNextMissionStep(state.pylone.currentStep);
+        if (nextStep === "done") {
+          return {
+            mainState: "ferme",
+            pylone: {
+              ...state.pylone,
+              currentStep: "done",
+              isPowered: true,
+            },
+            ferme: {
+              ...state.ferme,
+              currentStep: "inspected",
+            },
+          };
+        }
+
+        return { pylone: { ...state.pylone, currentStep: nextStep } };
+      }
+
+      if (state.mainState === "ferme") {
+        const nextStep = getNextMissionStep(state.ferme.currentStep);
+        if (nextStep === "done") {
+          return {
+            mainState: "outro",
+            ferme: {
+              ...state.ferme,
+              currentStep: "done",
+              irrigationFixed: true,
+            },
+            outro: {
+              ...state.outro,
+              hasStarted: true,
+            },
+          };
+        }
+
+        return { ferme: { ...state.ferme, currentStep: nextStep } };
+      }
+
+      return {
+        outro: {
+          ...state.outro,
+          hasStarted: true,
+        },
+      };
+    }),
   resetGame: () => set(createInitialGameState()),
 }));
diff --git a/src/pages/page.tsx b/src/pages/page.tsx
index 2635e63..a601019 100644
--- a/src/pages/page.tsx
+++ b/src/pages/page.tsx
@@ -1,6 +1,7 @@
 import { Suspense } from "react";
 import { Canvas } from "@react-three/fiber";
 import { Crosshair } from "@/components/ui/Crosshair";
+import { GameStateHUD } from "@/components/ui/GameStateHUD";
 import { InteractPrompt } from "@/components/ui/InteractPrompt";
 import { DebugPerf } from "@/components/debug/DebugPerf";
 import { World } from "@/world/World";
@@ -14,6 +15,7 @@ export function HomePage(): React.JSX.Element {
           <DebugPerf />
         </Suspense>
       </Canvas>
+      <GameStateHUD />
       <Crosshair />
       <InteractPrompt />
     </>
diff --git a/src/world/GameStageContent.tsx b/src/world/GameStageContent.tsx
new file mode 100644
index 0000000..ca16da8
--- /dev/null
+++ b/src/world/GameStageContent.tsx
@@ -0,0 +1,44 @@
+import { useGameStore } from "@/managers/stores/useGameStore";
+import type { Vector3Tuple } from "@/types/three";
+
+interface StageAnchorProps {
+  color: string;
+  position: Vector3Tuple;
+  scale?: number;
+}
+
+function StageAnchor({
+  color,
+  position,
+  scale = 1,
+}: StageAnchorProps): React.JSX.Element {
+  return (
+    <group position={position} scale={scale}>
+      <mesh>
+        <octahedronGeometry args={[1.2, 0]} />
+        <meshStandardMaterial
+          color={color}
+          emissive={color}
+          emissiveIntensity={0.25}
+        />
+      </mesh>
+    </group>
+  );
+}
+
+export function GameStageContent(): React.JSX.Element {
+  const mainState = useGameStore((state) => state.mainState);
+
+  switch (mainState) {
+    case "intro":
+      return <StageAnchor color="#7dd3fc" position={[0, 4, 0]} />;
+    case "bike":
+      return <StageAnchor color="#facc15" position={[8, 3, -6]} />;
+    case "pylone":
+      return <StageAnchor color="#a78bfa" position={[64, 6, -66]} />;
+    case "ferme":
+      return <StageAnchor color="#86efac" position={[-24, 5, 42]} />;
+    case "outro":
+      return <StageAnchor color="#fb7185" position={[0, 6, 10]} scale={1.25} />;
+  }
+}
diff --git a/src/world/World.tsx b/src/world/World.tsx
index b945c38..fe0344b 100644
--- a/src/world/World.tsx
+++ b/src/world/World.tsx
@@ -11,6 +11,7 @@ import { DebugHelpers } from "@/components/debug/scene/DebugHelpers";
 import { Environment } from "@/world/Environment";
 import { Lighting } from "@/world/Lighting";
 import { GameMap } from "@/world/GameMap";
+import { GameStageContent } from "@/world/GameStageContent";
 import { Player } from "@/world/player/Player";
 import { TestScene } from "@/world/debug/TestScene";
 
@@ -31,7 +32,10 @@ export function World(): React.JSX.Element {
       {cameraMode === "debug" ? <DebugCameraControls /> : null}
 
       {sceneMode === "game" ? (
-        <GameMap onOctreeReady={setOctree} />
+        <>
+          <GameMap onOctreeReady={setOctree} />
+          <GameStageContent />
+        </>
       ) : (
         <TestScene onOctreeReady={setOctree} />
       )}