diff --git a/game.scm b/game.scm
index d349bc9..1b7faab 100644
--- a/game.scm
+++ b/game.scm
@@ -56,19 +56,22 @@
 (define game-width 640.0)
 (define game-height 480.0)
 
-(define game-images `(('player . ,(make-image "assets/sprites/player.png"))
-                      ('barrel . ,(make-image "assets/sprites/barrel.png"))
-                      ('bricks . ,(make-image "assets/sprites/bricks.png"))
-                      ('stones . ,(make-image "assets/sprites/stones.png"))
-                      ('card-back . ,(make-image "assets/sprites/bricks.png"))))
+(define game-images `((player . ,(make-image "assets/sprites/player.png"))
+                      (barrel . ,(make-image "assets/sprites/barrel.png"))
+                      (bricks . ,(make-image "assets/sprites/bricks.png"))
+                      (stones . ,(make-image "assets/sprites/stones.png"))
+                      (card-back . ,(make-image "assets/sprites/bricks.png"))))
 
 (parameterize ((*logger* pk))
   (parameterize ((*media-library* (create-media-library)))
     (add-images! (get-media-library) game-images)
 
+    (define bootstrap-entity-manager (make-parameter #f))
+    (define bootstrap-system-manager (make-parameter #f))
     (write-log! "Creating entity manager")
-    (define e-manager
-      (create-entity-manager (init-game-entities)))
+    (define e-manager (parameterize ((*entity-manager-parameter* bootstrap-entity-manager)
+                                     (*system-manager-parameter* bootstrap-system-manager))
+                        (create-entity-manager (pk (init-game-entities)))))
 
     (write-log! "Creating system manager")
     (define s-manager
diff --git a/modules/ces/entity-manager.scm b/modules/ces/entity-manager.scm
index 3dc8d6c..5192200 100644
--- a/modules/ces/entity-manager.scm
+++ b/modules/ces/entity-manager.scm
@@ -46,7 +46,7 @@
   (case-lambda
     (() (create-entity-manager (emap:create-entity-map)))
     ((initial-world-state)
-     (make-entity-manager initial-world-state
+     (make-entity-manager (emap:create-entity-map initial-world-state)
                           (emap:create-entity-map)
                           (emap:create-entity-map)
                           (create-entity-generator)))
diff --git a/modules/ces/entity/entity-map.scm b/modules/ces/entity/entity-map.scm
index 092ad52..a8b51ff 100644
--- a/modules/ces/entity/entity-map.scm
+++ b/modules/ces/entity/entity-map.scm
@@ -1,6 +1,7 @@
 (define-module (ces entity entity-map)
   #:pure
   #:use-module (scheme base)
+  #:use-module (scheme case-lambda)
   #:use-module (hoot atomics)
   #:use-module (hoot hashtables)
   #:use-module (hoot match)
@@ -24,9 +25,27 @@
   entity-map?
   (entities entity-map-entities))
 
-(define (create-entity-map)
-  "Creates a new entity-map and returns it."
-  (make-entity-map (make-eq-hashtable)))
+(define create-entity-map
+  (case-lambda
+    (() (make-entity-map (make-eq-hashtable)))
+    ((initial-entities)
+     (cond
+      ((list? initial-entities)
+       (let ((initial-map (make-eq-hashtable)))
+         (for-each (lambda (val)
+                     (when (game-entity? val)
+                       (hashtable-set! initial-map
+                                       (game-entity-id val)
+                                       val)))
+                   initial-entities)
+         (make-entity-map initial-map)))
+      ((hashtable? initial-entities)
+       (make-entity-map initial-entities))
+      ((entity-map? initial-entities)
+       (make-entity-map
+        (hashtable-copy
+         (entity-map-entities initial-entities))))
+      (else (create-entity-map))))))
 
 (define (entity-key entity)
   "Returns the entity id of an entity, or the value itself if it is
diff --git a/modules/media.scm b/modules/media.scm
index 6c45000..5ef5f54 100644
--- a/modules/media.scm
+++ b/modules/media.scm
@@ -27,19 +27,17 @@
   (*media-library*))
 
 (define (create-media-library)
-  (write-log! "Creating media library.")
   (make-media-library (make-eq-hashtable)
                       (make-eq-hashtable)))
 
 (define (add-image! media-library image-symbol image)
-  (write-log! "Adding image: " image-symbol)
   (hashtable-set! (media-images media-library) image-symbol image))
 
 (define (add-images! media-library images)
-  (write-log! "Adding images: " images)
   (for-each (lambda (val)
               (add-image! media-library (car val) (cdr val)))
             images))
 
 (define (get-image media-library image-symbol)
-  (hashtable-ref (media-images media-library) image-symbol #f))
+  "Gets the image in the library, or 'image-not-found if the image does not exists."
+  (hashtable-ref (media-images media-library) image-symbol 'image-not-found))