diff --git a/src/asteroid.rs b/src/asteroid.rs
index be65918..a68c844 100644
--- a/src/asteroid.rs
+++ b/src/asteroid.rs
@@ -2,7 +2,7 @@ use bevy::prelude::*;
 use rand::{prelude::*, rng};
 
 use crate::{
-    FIRST_CORNER_X, FIRST_CORNER_Y, SECOND_CORNER_X, SECOND_CORNER_Y,
+    FIRST_CORNER_X, FIRST_CORNER_Y, GameState, SECOND_CORNER_X, SECOND_CORNER_Y,
     collision::{Collided, Collider},
     damagable::Damagable,
     projectile::Projectile,
@@ -15,8 +15,11 @@ pub struct AsteroidPlugin;
 
 impl Plugin for AsteroidPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(Startup, setup_asteroids)
-            .add_systems(FixedUpdate, rotate_asteroid);
+        app.add_systems(OnEnter(GameState::Game), setup_asteroids)
+            .add_systems(
+                FixedUpdate,
+                rotate_asteroid.run_if(in_state(GameState::Game)),
+            );
     }
 }
 
diff --git a/src/collision.rs b/src/collision.rs
index 39d25e1..a0b03a7 100644
--- a/src/collision.rs
+++ b/src/collision.rs
@@ -1,10 +1,15 @@
 use bevy::prelude::*;
 
+use crate::GameState;
+
 pub struct CollisionPlugin;
 
 impl Plugin for CollisionPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(FixedUpdate, calculate_collisions);
+        app.add_systems(
+            FixedUpdate,
+            calculate_collisions.run_if(in_state(GameState::Game)),
+        );
     }
 }
 
diff --git a/src/damagable.rs b/src/damagable.rs
index fbe082d..a23d1de 100644
--- a/src/damagable.rs
+++ b/src/damagable.rs
@@ -1,11 +1,16 @@
 use bevy::prelude::*;
 use std::default::Default;
 
+use crate::GameState;
+
 pub struct DamagablePlugin;
 
 impl Plugin for DamagablePlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(FixedPostUpdate, broken_ships_cleanup);
+        app.add_systems(
+            FixedPostUpdate,
+            broken_ships_cleanup.run_if(in_state(GameState::Game)),
+        );
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index 1ad221e..d9da3f8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -20,6 +20,13 @@ const FIRST_CORNER_Y: f32 = -512.;
 const SECOND_CORNER_X: f32 = 512.;
 const SECOND_CORNER_Y: f32 = 512.;
 
+#[derive(States, Debug, Clone, Hash, PartialEq, Eq)]
+pub enum GameState {
+    InMenu,
+    Game,
+    Gameover,
+}
+
 fn main() {
     App::new()
         .add_plugins(
@@ -37,6 +44,7 @@ fn main() {
                 })
                 .set(ImagePlugin::default_nearest()),
         )
+        .insert_state(GameState::Game)
         .add_plugins(VelocityPlugin)
         .add_plugins(CollisionPlugin)
         .add_plugins(ShipsPlugin)
diff --git a/src/projectile.rs b/src/projectile.rs
index af09c78..030b85f 100644
--- a/src/projectile.rs
+++ b/src/projectile.rs
@@ -1,6 +1,7 @@
 use bevy::prelude::*;
 
 use crate::{
+    GameState,
     collision::{Collided, Collider},
     damagable::Damagable,
     ships::Factions,
@@ -31,8 +32,11 @@ impl Projectile {
 
 impl Plugin for ProjectilePlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(Startup, projectile_startup)
-            .add_systems(FixedPreUpdate, projectile_despawn_countdown);
+        app.add_systems(OnEnter(GameState::Game), projectile_startup)
+            .add_systems(
+                FixedPreUpdate,
+                projectile_despawn_countdown.run_if(in_state(GameState::Game)),
+            );
     }
 }
 
diff --git a/src/ships/mod.rs b/src/ships/mod.rs
index 40ffbf4..85a35dd 100644
--- a/src/ships/mod.rs
+++ b/src/ships/mod.rs
@@ -1,6 +1,6 @@
 use bevy::prelude::*;
 
-use crate::projectile::spawn_projectile;
+use crate::GameState;
 
 pub mod enemy;
 pub mod player;
@@ -39,11 +39,11 @@ pub struct ShipsPlugin;
 impl Plugin for ShipsPlugin {
     fn build(&self, app: &mut bevy::app::App) {
         app.insert_resource(Time::<Fixed>::from_hz(60.))
-            .add_systems(Startup, startup)
+            .add_systems(OnEnter(GameState::Game), startup)
             .add_systems(
                 FixedUpdate,
                 (
-                    player::player_movement_system,
+                    player::player_movement_system.run_if(in_state(GameState::Game)),
                     player::player_shooting_system,
                 ),
             );
diff --git a/src/velocity.rs b/src/velocity.rs
index eb245c5..ae44d10 100644
--- a/src/velocity.rs
+++ b/src/velocity.rs
@@ -1,14 +1,17 @@
 use bevy::prelude::*;
 use std::default::Default;
 
-use crate::{FIRST_CORNER_X, FIRST_CORNER_Y, SECOND_CORNER_X, SECOND_CORNER_Y};
+use crate::{FIRST_CORNER_X, FIRST_CORNER_Y, GameState, SECOND_CORNER_X, SECOND_CORNER_Y};
 
 pub struct VelocityPlugin;
 
 impl Plugin for VelocityPlugin {
     fn build(&self, app: &mut App) {
         app.insert_resource(Time::<Fixed>::from_hz(60.0))
-            .add_systems(FixedUpdate, movement_system);
+            .add_systems(
+                FixedUpdate,
+                movement_system.run_if(in_state(GameState::Game)),
+            );
     }
 }