diff --git a/src/hottub/core.clj b/src/hottub/core.clj
index b29c5f8..2527b27 100644
--- a/src/hottub/core.clj
+++ b/src/hottub/core.clj
@@ -3,33 +3,74 @@
             [hottub.gs :as gs]
             [hottub.resource :as res]
             [hottub.timeline :as tln]
-            [hottub.screen :as scr]))
+            [hottub.screen :as scr]
+            [hottub.util :as u]))
 
 (defn -main [& args]
   (res/start-resource-expiry-thread)
   (slick/start-game "Test game" {:id :game}))
 
 (defmethod scr/screen-from-spec :game [spec]
-  {:gs (gs/update-gs gs/gs-empty
-                     (gs/add-index :name)
-                     (gs/add-index :type)
-                     (gs/set-entity (gs/gen-id) {:type :sprite :x 50 :y 50 
-                                                 :image "res/man.png" :name :man}))})
+  {:tln (tln/timeline-insert (tln/timeline-create) 0
+                             (gs/update-gs gs/gs-empty
+                               (gs/add-index :name)
+                               (gs/add-index :type)
+                               (gs/set-entity (gs/gen-id) {:type :sprite :x 50 :y 50 
+                                                           :image "res/man.png" :name :man})))
+   :timestamp-last (u/timestamp)})
 
-(defmethod scr/spec-from-screen :game [screen] {:id :game})
+(defn update-gs [input]
+  (let [man (first (gs/q :name :man))]
+    (gs/update-entity (assoc man :x (:mousex input) :y (:mousey input)))))
 
-(defmethod slick/update-game :game [state inputtln delta]
-  (assoc state :gs (gs/update-gs (:gs state)
-    (if-let [input (tln/timeline-last-value inputtln)]
-      (let [man (first (gs/q :name :man))]
-        (gs/update-entity (assoc man :x (:mousex input) :y (:mousey input))))))))
-
-(defmethod slick/render-game :game [state graphics]
-  (gs/with-gs (:gs state)
+(defn render-gs [gs]
+  (gs/with-gs gs
     (doseq [sprite (gs/q :type :sprite)]
       (if-let [image (res/get-image (:image sprite))]
         (.draw image (:x sprite) (:y sprite))))))
 
+(defmethod slick/update-game :game [screen inputtln delta]
+  (if-let [input (tln/timeline-last-value inputtln)]
+    (if (contains? (:keys input) ",")
+      (scr/push-modal-screen screen 
+                             {:id :timeshift
+                              :ts (-> (:tln screen) last key)})
+      
+      (let [ts         (u/timestamp)
+            screentslast (-> (:tln screen) last key)
+            screents   (+ screentslast (- ts (:timestamp-last screen)))
+            tln        (:tln screen)
+            gslast     (tln/timeline-last-value tln)
+            gsnext     (gs/update-gs gslast (update-gs input))
+            tlnnext    (tln/timeline-insert tln screents gsnext)
+            screennext (assoc screen :timestamp-last ts :tln tlnnext)]
+        (scr/update-screen screen screennext)))))
+
+(defmethod slick/render-game :game [screen graphics]
+  (render-gs (tln/timeline-last-value (:tln screen))))
+
+(defmethod slick/update-game :timeshift [screen inputtln delta]
+  (let [input-from-tln (tln/timeline-last-value inputtln)
+        input-from-screen (:input screen)
+        input (or input-from-tln input-from-screen)
+        keys (:keys input)]
+    (if (contains? keys " ")
+      (scr/pop-modal-screen screen)
+      (let [ts (:ts screen)
+            ts (cond
+                 (contains? keys ",") (- ts delta)
+                 (contains? keys ".") (+ ts delta)
+                 :else ts)
+            screennext (assoc screen :ts ts :input input)]
+        (scr/update-screen screen screennext)))))
+
+(defmethod slick/render-game :timeshift [screen graphics]
+  (let [subscreen (scr/screen-behind-modal screen)
+        tln (:tln subscreen)
+        ts (tln/time-nearest tln (:ts screen))
+        gs (last (get tln ts))]
+    (render-gs gs)))
+
 ;;; repl helpers
 (def ^:dynamic g nil)
 (def ^:dynamic s nil)
@@ -40,4 +81,4 @@
 (defmethod slick/eval-with-bindings :default [state game f]
   (binding [g game s state *newscreen* (atom nil)] 
     (let [gsnew (gs/update-gs (:gs state) (f))]
-      (slick/game-setstate! game (or @*newscreen* (assoc state :gs gsnew))))))
+      (slick/game-setscreen! game (or @*newscreen* (assoc state :gs gsnew))))))