diff --git a/app/ecs/systems/colliders.js b/app/ecs/systems/colliders.js
index 0485640..4c96a68 100644
--- a/app/ecs/systems/colliders.js
+++ b/app/ecs/systems/colliders.js
@@ -39,32 +39,31 @@ export default class Colliders extends System {
   }
 
   tick() {
-    const seen = {};
+    const collisions = new Map();
+    for (const entity of this.ecs.changed(['Position'])) {
+      this.updateHash(entity);
+    }
     for (const entity of this.ecs.changed(['Position'])) {
-      if (seen[entity.id]) {
-        continue;
-      }
-      seen[entity.id] = true;
       if (!entity.Collider) {
         continue;
       }
-      const {collidingWith: wasCollidingWith} = entity.Collider;
-      entity.Collider.collidingWith = {};
-      this.updateHash(entity);
+      collisions.set(entity, new Set());
       for (const other of this.within(entity.Collider.aabb)) {
-        if (seen[other.id]) {
+        if (entity === other) {
           continue;
         }
-        seen[other.id] = true;
-        if (!other.Collider) {
+        if (!collisions.has(other)) {
+          collisions.set(other, new Set());
+        }
+        if (!other.Collider || collisions.get(other).has(entity)) {
           continue;
         }
-        delete other.Collider.collidingWith[entity.id];
         const intersections = entity.Collider.isCollidingWith(other.Collider);
         if (intersections.length > 0) {
-          entity.Collider.collidingWith[other.id] = true;
-          other.Collider.collidingWith[entity.id] = true;
-          if (!wasCollidingWith[other.id]) {
+          collisions.get(entity).add(other);
+          if (!entity.Collider.collidingWith[other.id]) {
+            entity.Collider.collidingWith[other.id] = true;
+            other.Collider.collidingWith[entity.id] = true;
             if (entity.Collider.collisionStartScriptInstance) {
               const script = entity.Collider.collisionStartScriptInstance.clone();
               script.context.intersections = intersections;
@@ -117,22 +116,20 @@ export default class Colliders extends System {
             }
           }
         }
-      }
-      for (const otherId in wasCollidingWith) {
-        if (!entity.Collider.collidingWith[otherId]) {
-          const other = this.ecs.get(otherId);
-          if (!other || !other.Collider) {
-            continue;
-          }
-          if (entity.Collider.collisionEndScriptInstance) {
-            const script = entity.Collider.collisionEndScriptInstance.clone();
-            script.context.other = other;
-            entity.Ticking.add(script.ticker());
-          }
-          if (other.Collider.collisionEndScriptInstance) {
-            const script = other.Collider.collisionEndScriptInstance.clone();
-            script.context.other = entity;
-            other.Ticking.add(script.ticker());
+        else {
+          if (entity.Collider.collidingWith[other.id]) {
+            if (entity.Collider.collisionEndScriptInstance) {
+              const script = entity.Collider.collisionEndScriptInstance.clone();
+              script.context.other = other;
+              entity.Ticking.add(script.ticker());
+            }
+            if (other.Collider.collisionEndScriptInstance) {
+              const script = other.Collider.collisionEndScriptInstance.clone();
+              script.context.other = entity;
+              other.Ticking.add(script.ticker());
+            }
+            delete entity.Collider.collidingWith[other.id];
+            delete other.Collider.collidingWith[entity.id];
           }
         }
       }