diff --git a/Cargo.lock b/Cargo.lock
index 6cacabe..7471a01 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -791,6 +791,7 @@ version = "0.1.0"
 name = "moonhare_game"
 version = "0.1.0"
 dependencies = [
+ "moonhare_ecs",
  "moonhare_graphics",
  "moonhare_log",
  "moonhare_window",
diff --git a/crates/moonhare_ecs/src/component.rs b/crates/moonhare_ecs/src/component.rs
new file mode 100644
index 0000000..7a0ab09
--- /dev/null
+++ b/crates/moonhare_ecs/src/component.rs
@@ -0,0 +1,20 @@
+use std::{collections::HashMap, marker::PhantomData};
+
+use crate::generational_index::{self, GenerationalIndex};
+
+#[derive(Debug)]
+pub struct Component<T: ComponentType> {
+    id: usize,
+    component_type: T,
+}
+
+pub trait ComponentType{}
+
+impl<T: ComponentType> Component<T> {
+    pub fn new(id: usize, component_type: T) -> Self {
+        Self { 
+            id, 
+            component_type
+        }
+    }
+}
\ No newline at end of file
diff --git a/crates/moonhare_ecs/src/entity/mod.rs b/crates/moonhare_ecs/src/entity/mod.rs
new file mode 100644
index 0000000..964313e
--- /dev/null
+++ b/crates/moonhare_ecs/src/entity/mod.rs
@@ -0,0 +1,36 @@
+use crate::{entity, generational_index::{GenerationalIndex, GenerationalIndexAllocator}};
+
+#[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone, Copy, Hash)]
+pub struct Entity(GenerationalIndex);
+
+impl Entity {
+    pub fn index(&self) -> usize {
+        self.0.index()
+    }
+
+    pub fn generation(&self) -> u64 {
+        self.0.generation()
+    }
+}
+
+
+#[derive(Debug, Clone)]
+pub struct EntityAllocator(GenerationalIndexAllocator);
+
+impl EntityAllocator {
+    pub fn new() -> Self {
+        EntityAllocator(GenerationalIndexAllocator::new())
+    }
+
+    pub fn allocate(&mut self) -> Entity {
+        Entity(self.0.allocate())
+    }
+
+    pub fn deallocate(&mut self, entity: Entity) -> bool {
+        self.0.deallocate(entity.0)
+    }
+
+    pub fn is_live(&self, entity: Entity) -> bool {
+        self.0.is_live(entity.0)
+    }
+}
\ No newline at end of file
diff --git a/crates/moonhare_ecs/src/generational_index.rs b/crates/moonhare_ecs/src/generational_index.rs
index 2def46f..e68a0b6 100644
--- a/crates/moonhare_ecs/src/generational_index.rs
+++ b/crates/moonhare_ecs/src/generational_index.rs
@@ -1,4 +1,4 @@
-#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
 pub struct GenerationalIndex {
     index: usize,
     generation: u64,
@@ -14,17 +14,22 @@ impl GenerationalIndex {
     }
 }
 
+#[derive(Debug, Clone)]
 struct AllocatorEntry {
     is_live: bool,
     generation: u64,
 }
 
+#[derive(Debug, Clone, Default)]
 pub struct GenerationalIndexAllocator {
     entries: Vec<AllocatorEntry>,
     free: Vec<usize>,
 }
 
 impl GenerationalIndexAllocator {
+    pub fn new() -> Self {
+        Default::default()
+    }
     pub fn allocate(&mut self) -> GenerationalIndex {
         match self.free.pop() {
             Some(index) =>{
@@ -64,6 +69,10 @@ impl GenerationalIndexAllocator {
     pub fn is_live(&self, index: GenerationalIndex) -> bool {
         index.index() < self.entries.len() && self.entries[index.index()].generation == index.generation && self.entries[index.index()].is_live
     }
+
+    pub fn max_allocated_index(&self) -> usize {
+        self.entries.len()
+    }
 }
 
 struct ArrayEntry<T> {
@@ -74,7 +83,15 @@ struct ArrayEntry<T> {
 pub struct GenerationalIndexArray<T>(Vec<Option<ArrayEntry<T>>>);
 
 impl <T> GenerationalIndexArray<T> {
-    pub fn set(&mut self, index: GenerationalIndex, value: T) {
+    pub fn new() -> GenerationalIndexArray<T> {
+        GenerationalIndexArray(Vec::new())
+    }
+
+    pub fn clear(&mut self) {
+        self.0.clear();
+    }
+    
+    pub fn insert(&mut self, index: GenerationalIndex, value: T) {
         while self.0.len() <= index.index()  {
             self.0.push(None);
         }
diff --git a/crates/moonhare_ecs/src/lib.rs b/crates/moonhare_ecs/src/lib.rs
index 6a9fc59..da147cf 100644
--- a/crates/moonhare_ecs/src/lib.rs
+++ b/crates/moonhare_ecs/src/lib.rs
@@ -1,15 +1,55 @@
+use std::{collections::HashMap, path::{Component, Components}};
+
 use anymap::AnyMap;
 
-use crate::generational_index::{GenerationalIndex, GenerationalIndexAllocator, GenerationalIndexArray};
+use crate::{entity::{Entity, EntityAllocator}, generational_index::{GenerationalIndex, GenerationalIndexAllocator, GenerationalIndexArray}};
 
 pub mod generational_index;
+pub mod world;
+pub mod entity;
+pub mod component;
 
-pub type Entity = GenerationalIndex;
-pub type EntityMap<T> = GenerationalIndexArray<T>;
 
 // based on: https://kyren.github.io/2018/09/14/rustconf-talk.html
+
+/* Moonhare ECS Design
+--------------------------------------
+                 Game
+                  🠟
+                Systems
+(RenderSystem, PhysicsSystem, EnemyAISystem, EnemyCollisionSystem,...)   
+                  🠟
+                Entity
+                  🠟    
+               Components
+--------------------------------------               
+*/
+
+#[derive(Debug)]
 pub struct ECS {
-    pub entity_allocator: GenerationalIndexAllocator,
-    pub entity_components: AnyMap,
-    pub resources: AnyMap
-}
\ No newline at end of file
+    entities: EntityAllocator,
+    components: AnyMap
+}
+
+impl ECS {
+    pub fn new() -> ECS {
+        ECS { 
+            entities: EntityAllocator::new(),
+            components: AnyMap::new(), 
+        }
+    }
+
+    pub fn add_entity(&mut self) -> Entity {
+        self.entities.allocate()
+    }
+
+    pub fn entity_is_live(&self, entity: Entity) -> bool {
+        self.entities.is_live(entity)
+    }
+
+    pub fn register_component() {
+        
+    }
+
+}
+
diff --git a/crates/moonhare_ecs/src/world.rs b/crates/moonhare_ecs/src/world.rs
new file mode 100644
index 0000000..bd3bac7
--- /dev/null
+++ b/crates/moonhare_ecs/src/world.rs
@@ -0,0 +1,22 @@
+use std::fmt::Error;
+
+use anymap::AnyMap;
+
+use crate::{Entity, ECS};
+
+/// stores Entitys, Components and resources
+/// provides methods to search for specific Entitys 
+#[derive(Debug)]
+pub struct World {
+    ecs: ECS,
+    resources: AnyMap
+}
+
+impl World {
+    pub fn new() -> Self {
+        Self { 
+            ecs: ECS::new(),
+            resources: AnyMap::new(), 
+        }
+    }
+}
\ No newline at end of file
diff --git a/crates/moonhare_game/Cargo.toml b/crates/moonhare_game/Cargo.toml
index 2800e98..97d9f14 100644
--- a/crates/moonhare_game/Cargo.toml
+++ b/crates/moonhare_game/Cargo.toml
@@ -5,6 +5,7 @@ version.workspace = true
 authors.workspace = true
 
 [dependencies]
+moonhare_ecs = { path = "../moonhare_ecs" }
 moonhare_graphics = { path = "../moonhare_graphics" }
 moonhare_log = { path = "../moonhare_log" }
 moonhare_window = { path = "../moonhare_window" }
diff --git a/crates/moonhare_game/src/lib.rs b/crates/moonhare_game/src/lib.rs
index 5ff365c..add2b6e 100644
--- a/crates/moonhare_game/src/lib.rs
+++ b/crates/moonhare_game/src/lib.rs
@@ -2,6 +2,8 @@
 
 use std::rc::Rc;
 
+
+use moonhare_ecs::world::World;
 use moonhare_graphics::{color::Color, glium::{backend::Context, glutin::api::egl::context}};
 use moonhare_log::*;
 use moonhare_window::{platforms::glfw_window::GLFWWindow};
@@ -10,19 +12,17 @@ pub mod basic;
 /// Only one Game may exist per project
 #[derive(Debug)]
 pub struct Game {
+    pub world: World,
     pub is_running: bool,
     pub name: String,
-    pub context: moonhare_window::WindowRenderContext,
-    pub glfw_window: Option<moonhare_window::platforms::glfw_window::GLFWWindow>,
 }
 
 impl Default for Game {
     fn default() -> Self {
         Self { 
+            world: World::new(),
             is_running: true,
             name: default_game_name(),
-            context: moonhare_window::WindowRenderContext::OPENGLGLFW,
-            glfw_window: None,
         }
     }
 }