diff --git a/GameCore/Combat/Effects/MeleeEffect.cs b/GameCore/Combat/Effects/MeleeEffect.cs
new file mode 100644
index 0000000..dea506a
--- /dev/null
+++ b/GameCore/Combat/Effects/MeleeEffect.cs
@@ -0,0 +1,29 @@
+using GameCore.Combat.Interfaces;
+using GameCore.Input;
+
+namespace GameCore.Combat.Effects;
+
+public class MeleeEffect(float range, float radius) : IEffect
+{
+    public void Execute(EffectContext context)
+    {
+        var input = context.World.GetComponent<InputStateComponent>(context.Owner);
+        var weapon = context.World.GetComponent<WeaponComponent>(context.Owner);
+        if (input == null || weapon == null) return;
+
+        var checkPosition = input.MuzzlePosition + input.MuzzleDirection * range;
+        var hits = context.World.WorldQuery.OverlapSphere(checkPosition, radius, context.Owner);
+
+        foreach (var hitEntity in hits)
+        {
+            var hitContext = new EffectContext
+            {
+                World = context.World,
+                Owner = context.Owner,
+                Target = hitEntity
+            };
+
+            foreach (var effect in weapon.OnHitEffects) effect.Execute(hitContext);
+        }
+    }
+}
\ No newline at end of file
diff --git a/GameCore/ECS/Interfaces/IWorldQuery.cs b/GameCore/ECS/Interfaces/IWorldQuery.cs
index 697ef80..81d2223 100644
--- a/GameCore/ECS/Interfaces/IWorldQuery.cs
+++ b/GameCore/ECS/Interfaces/IWorldQuery.cs
@@ -6,4 +6,5 @@ public interface IWorldQuery
 {
     HitResult Raycast(Vector3 from, Vector3 to, Entity? ownerToExclude = null);
     Vector3 RotateVectorByYaw(Vector3 vector, float yawRadians);
+    IEnumerable<Entity> OverlapSphere(Vector3 position, float radius, Entity? ownerToExclude = null);
 }
\ No newline at end of file
diff --git a/GameCore/ECS/World.cs b/GameCore/ECS/World.cs
index 876d609..3380c19 100644
--- a/GameCore/ECS/World.cs
+++ b/GameCore/ECS/World.cs
@@ -5,6 +5,8 @@ using GameCore.Events.Interfaces;
 using GameCore.Input.Interfaces;
 using GameCore.Interaction;
 using GameCore.Logging.Interfaces;
+using GameCore.Services;
+using GameCore.State;
 
 namespace GameCore.ECS;
 
@@ -13,18 +15,37 @@ namespace GameCore.ECS;
 ///     It manages all entities, components, and systems, and orchestrates the main game loop.
 ///     This class is the primary point of interaction for the Engine/Presentation layer.
 /// </summary>
-public class World(IInputService inputService, IWorldQuery worldQuery, SimulationConfig config, ILogger logger)
+public class World
 {
     private readonly Dictionary<int, List<IComponent>> _componentsByEntityId = new();
     private readonly EventBus _eventBus = new();
     private readonly List<ISystem> _systems = [];
+    public readonly IAudioService AudioService;
 
-    public readonly SimulationConfig Config = config;
-    public readonly IInputService InputService = inputService;
-    public readonly ILogger Logger = logger;
-    public readonly IWorldQuery WorldQuery = worldQuery;
+    public readonly SimulationConfig Config;
+    public readonly IGameStateService GameState;
+    public readonly IInputService InputService;
+    public readonly ILogger Logger;
+    public readonly IParticleService ParticleService;
+    public readonly IWorldQuery WorldQuery;
     private int _nextEntityId;
 
+    public World(IInputService inputService,
+        IWorldQuery worldQuery,
+        SimulationConfig config,
+        ILogger logger,
+        IAudioService audioService,
+        IParticleService particleService)
+    {
+        AudioService = audioService;
+        Config = config;
+        InputService = inputService;
+        Logger = logger;
+        ParticleService = particleService;
+        WorldQuery = worldQuery;
+        GameState = new GameStateService(this);
+    }
+
     /// <summary>
     ///     Creates a new, unique entity.
     /// </summary>
diff --git a/GameCore/Events/GameStatusChangedEvent.cs b/GameCore/Events/GameStatusChangedEvent.cs
new file mode 100644
index 0000000..0da36bd
--- /dev/null
+++ b/GameCore/Events/GameStatusChangedEvent.cs
@@ -0,0 +1,9 @@
+using GameCore.Events.Interfaces;
+using GameCore.State;
+
+namespace GameCore.Events;
+
+public readonly struct GameStatusChangedEvent(GameStatus newStatus) : IEvent
+{
+    public readonly GameStatus NewStatus = newStatus;
+}
\ No newline at end of file
diff --git a/GameCore/Services/IAudioService.cs b/GameCore/Services/IAudioService.cs
new file mode 100644
index 0000000..23feada
--- /dev/null
+++ b/GameCore/Services/IAudioService.cs
@@ -0,0 +1,9 @@
+using GameCore.Math;
+
+namespace GameCore.Services;
+
+public interface IAudioService
+{
+    void Play(string soundId);
+    void PlayAtPoint(string soundId, Vector3 position);
+}
\ No newline at end of file
diff --git a/GameCore/Services/IParticleService.cs b/GameCore/Services/IParticleService.cs
new file mode 100644
index 0000000..736724a
--- /dev/null
+++ b/GameCore/Services/IParticleService.cs
@@ -0,0 +1,9 @@
+using GameCore.Math;
+
+namespace GameCore.Services;
+
+public interface IParticleService
+{
+    void Trigger(string particleId, Vector3 position);
+    void Trigger(string particleId, Vector3 position, Vector3 normal);
+}
\ No newline at end of file
diff --git a/GameCore/State/GameStateService.cs b/GameCore/State/GameStateService.cs
new file mode 100644
index 0000000..26f0880
--- /dev/null
+++ b/GameCore/State/GameStateService.cs
@@ -0,0 +1,40 @@
+using GameCore.ECS;
+using GameCore.Events;
+
+namespace GameCore.State;
+
+public class GameStateService(World world) : IGameStateService
+{
+    private readonly HashSet<string> _unlockedLevelIds = [];
+    private readonly World _world = world;
+    public GameStatus CurrentStatus { get; private set; } = GameStatus.InMainMenu;
+    public string CurrentLevelId { get; private set; }
+    public IReadOnlyCollection<string> UnlockedLevelIds => _unlockedLevelIds;
+
+    public void SetStatus(GameStatus newStatus)
+    {
+        if (CurrentStatus == newStatus) return;
+
+        CurrentStatus = newStatus;
+        _world.PublishEvent(new GameStatusChangedEvent(newStatus));
+    }
+
+    public void StartGame(string startingLevelId)
+    {
+        CurrentLevelId = startingLevelId;
+        _unlockedLevelIds.Add(startingLevelId);
+        SetStatus(GameStatus.InGame);
+    }
+
+    public void UnlockLevel(string levelId)
+    {
+        _unlockedLevelIds.Add(levelId);
+    }
+
+    public void ResetProgress()
+    {
+        _unlockedLevelIds.Clear();
+        CurrentLevelId = null!;
+        SetStatus(GameStatus.InMainMenu);
+    }
+}
\ No newline at end of file
diff --git a/GameCore/State/GameStatus.cs b/GameCore/State/GameStatus.cs
new file mode 100644
index 0000000..8300ed8
--- /dev/null
+++ b/GameCore/State/GameStatus.cs
@@ -0,0 +1,9 @@
+namespace GameCore.State;
+
+public enum GameStatus
+{
+    InMainMenu,
+    InGame,
+    Paused,
+    GameOver
+}
\ No newline at end of file
diff --git a/GameCore/State/IGameStateService.cs b/GameCore/State/IGameStateService.cs
new file mode 100644
index 0000000..b296f50
--- /dev/null
+++ b/GameCore/State/IGameStateService.cs
@@ -0,0 +1,13 @@
+namespace GameCore.State;
+
+public interface IGameStateService
+{
+    GameStatus CurrentStatus { get; }
+    string CurrentLevelId { get; }
+    IReadOnlyCollection<string> UnlockedLevelIds { get; }
+
+    void SetStatus(GameStatus newStatus);
+    void StartGame(string startingLevelId);
+    void UnlockLevel(string levelId);
+    void ResetProgress();
+}
\ No newline at end of file