diff --git a/src/play_clj/repl.clj b/src/play_clj/repl.clj
new file mode 100644
index 0000000..2ccde12
--- /dev/null
+++ b/src/play_clj/repl.clj
@@ -0,0 +1,27 @@
+(ns play-clj.repl
+  (:require [clojure.pprint :refer :all]
+            [play-clj.core :refer :all]))
+
+(defn entities
+  "Returns the entities in `screen-object`, optionally filtered by a supplied
+function.
+
+    (entities main-screen :player)"
+  ([screen-object]
+    (-> screen-object :entities deref))
+  ([screen-object filter-fn]
+    (filter filter-fn (entities screen-object))))
+
+(defn entities!
+  "Associates values to the entities in `screen-object` that match the supplied
+function.
+
+    (entities! main-screen :player :health 10)"
+  [screen-object filter-fn & args]
+  (on-gl (swap! (:entities screen-object)
+                (fn [entities]
+                  (for [e entities]
+                    (if (filter-fn e)
+                      (apply assoc e args)
+                      e)))))
+  (entities screen-object filter-fn))