diff --git a/app/ecs/ecs.js b/app/ecs/ecs.js
index 3915f1f..6fa4fe3 100644
--- a/app/ecs/ecs.js
+++ b/app/ecs/ecs.js
@@ -22,6 +22,8 @@ export default class Ecs {
 
   deferredChanges = {}
 
+  destroying = new Set();
+
   diff = {};
 
   Systems = {};
@@ -206,6 +208,10 @@ export default class Ecs {
   }
 
   destroy(entityId) {
+    this.destroying.add(entityId);
+  }
+
+  destroyImmediately(entityId) {
     this.destroyMany([entityId]);
   }
 
@@ -427,31 +433,24 @@ export default class Ecs {
   }
 
   tick(elapsed) {
-    const destroying = new Set();
     for (const systemName in this.Systems) {
       const System = this.Systems[systemName];
-      if (System.active) {
-        if (System.frequency) {
-          System.elapsed += elapsed;
-          if (System.elapsed < System.frequency) {
-            continue;
-          }
-        }
-        while (!System.frequency || System.elapsed >= System.frequency) {
-          System.tick(System.frequency ? System.elapsed : elapsed);
-          for (let j = 0; j < System.destroying.length; j++) {
-            destroying.add(System.destroying[j]);
-          }
-          System.tickDestruction();
-          if (!System.frequency) {
-            break;
-          }
-          System.elapsed -= System.frequency;
-        }
+      if (!System.active) {
+        continue;
+      }
+      if (!System.frequency) {
+        System.tick(elapsed);
+        continue;
+      }
+      System.elapsed += elapsed;
+      while (System.elapsed >= System.frequency) {
+        System.tick(System.frequency);
+        System.elapsed -= System.frequency;
       }
     }
-    if (destroying.size > 0) {
-      this.destroyMany(destroying.values());
+    if (this.destroying.size > 0) {
+      this.destroyMany(this.destroying);
+      this.destroying.clear();
     }
   }
 
diff --git a/app/ecs/ecs.test.js b/app/ecs/ecs.test.js
index f72dcc0..808b031 100644
--- a/app/ecs/ecs.test.js
+++ b/app/ecs/ecs.test.js
@@ -114,7 +114,7 @@ test('destroys entities', async () => {
   expect(ecs.get(entity))
     .to.be.undefined;
   expect(() => {
-    ecs.destroy(entity);
+    ecs.destroyImmediately(entity);
   })
     .to.throw();
 });
@@ -170,50 +170,14 @@ test('ticks systems', async () => {
     .to.deep.equal(JSON.stringify({y: 128 + 30}));
 });
 
-test('creates many entities when ticking systems', () => {
-  const ecs = new Ecs({
-    Systems: {
-      Spawn: class extends System {
-        tick() {
-          this.createManyEntities(Array.from({length: 5}).map(() => []));
-        }
-      },
-    },
-  });
-  ecs.system('Spawn').active = true;
-  ecs.create();
-  expect(ecs.get(5))
-    .to.be.undefined;
-  ecs.tick(1);
-  expect(ecs.get(5))
-    .to.not.be.undefined;
-});
-
-test('creates entities when ticking systems', () => {
-  const ecs = new Ecs({
-    Systems: {
-      Spawn: class extends System {
-        tick() {
-          this.createEntity();
-        }
-      },
-    },
-  });
-  ecs.system('Spawn').active = true;
-  ecs.create();
-  expect(ecs.get(2))
-    .to.be.undefined;
-  ecs.tick(1);
-  expect(ecs.get(2))
-    .to.not.be.undefined;
-});
-
 test('schedules entities to be deleted when ticking systems', () => {
   const ecs = new Ecs({
     Systems: {
       Despawn: class extends System {
         tick() {
-          this.destroyEntity(1);
+          this.ecs.destroy(1);
+          expect(ecs.get(1))
+            .to.not.be.undefined;
         }
       },
     },
@@ -225,50 +189,6 @@ test('schedules entities to be deleted when ticking systems', () => {
     .to.be.undefined;
 });
 
-test('adds components to and remove components from entities when ticking systems', async () => {
-  let promise;
-  const ecs = new Ecs({
-    Components: {Foo: wrapProperties('Foo', {bar: {type: 'uint8'}})},
-    Systems: {
-      AddComponent: class extends System {
-        static queries() {
-          return {
-            default: ['Foo'],
-          };
-        }
-        tick() {
-          promise = this.insertComponents(1, {Foo: {}});
-        }
-      },
-      RemoveComponent: class extends System {
-        static queries() {
-          return {
-            default: ['Foo'],
-          };
-        }
-        tick() {
-          this.removeComponents(1, ['Foo']);
-        }
-      },
-    },
-  });
-  ecs.system('AddComponent').active = true;
-  ecs.create();
-  ecs.tick(1);
-  await promise;
-  expect(Array.from(ecs.system('AddComponent').select('default')).length)
-    .to.equal(1);
-  expect(ecs.get(1).Foo)
-    .to.not.be.undefined;
-  ecs.system('AddComponent').active = false;
-  ecs.system('RemoveComponent').active = true;
-  ecs.tick(1);
-  expect(Array.from(ecs.system('RemoveComponent').select('default')).length)
-    .to.equal(0);
-  expect(ecs.get(1).Foo)
-    .to.be.undefined;
-});
-
 test('generates diffs for entity creation', async () => {
   const ecs = new Ecs();
   let entity;
@@ -347,7 +267,7 @@ test('generates diffs for deletions', async () => {
   let entity;
   entity = await ecs.create();
   ecs.setClean();
-  ecs.destroy(entity);
+  ecs.destroyImmediately(entity);
   expect(ecs.diff)
     .to.deep.equal({[entity]: false});
 });
diff --git a/app/ecs/system.js b/app/ecs/system.js
index 9b6d381..1bded49 100644
--- a/app/ecs/system.js
+++ b/app/ecs/system.js
@@ -6,8 +6,6 @@ export default class System {
 
   active = false;
 
-  destroying = [];
-
   ecs;
 
   elapsed = 0;
@@ -25,38 +23,12 @@ export default class System {
     this.reindex(ecs.entities);
   }
 
-  createEntity(components) {
-    return this.ecs.create(components);
-  }
-
-  createManyEntities(componentsList) {
-    return this.ecs.createMany(componentsList);
-  }
-
   deindex(entityIds) {
     for (const i in this.queries) {
       this.queries[i].deindex(entityIds);
     }
   }
 
-  destroyEntity(entityId) {
-    this.destroyManyEntities([entityId]);
-  }
-
-  destroyManyEntities(entityIds) {
-    for (let i = 0; i < entityIds.length; i++) {
-      this.destroying.push(entityIds[i]);
-    }
-  }
-
-  async insertComponents(entityId, components) {
-    return this.ecs.insert(entityId, components);
-  }
-
-  async insertManyComponents(components) {
-    return this.ecs.insertMany(components);
-  }
-
   static get priority() {
     return {
       phase: 'normal',
@@ -73,14 +45,6 @@ export default class System {
     }
   }
 
-  removeComponents(entityId, components) {
-    this.ecs.remove(entityId, components);
-  }
-
-  removeManyComponents(entityIds) {
-    this.ecs.removeMany(entityIds);
-  }
-
   select(query) {
     return this.queries[query].select();
   }
@@ -117,13 +81,6 @@ export default class System {
     );
   }
 
-  tickDestruction() {
-    if (this.destroying.length > 0) {
-      this.deindex(this.destroying);
-    }
-    this.destroying = [];
-  }
-
   tick() {}
 
 }
diff --git a/app/server/engine.js b/app/server/engine.js
index 56ed3ac..613e779 100644
--- a/app/server/engine.js
+++ b/app/server/engine.js
@@ -322,6 +322,7 @@ export default class Engine {
   stop() {
     clearTimeout(this.handle);
     this.handle = undefined;
+    this.tick(0);
   }
 
   tick(elapsed) {
diff --git a/app/server/worker.js b/app/server/worker.js
index b04354a..7cf74a7 100644
--- a/app/server/worker.js
+++ b/app/server/worker.js
@@ -45,8 +45,8 @@ const engine = new Engine(WorkerServer);
 
 onmessage = async (event) => {
   if (0 === event.data) {
-    engine.stop();
     await engine.disconnectPlayer(0);
+    engine.stop();
     await engine.saveEcses();
     postMessage(0);
     return;