diff --git a/project.clj b/project.clj
index 0a14375..cc12e07 100644
--- a/project.clj
+++ b/project.clj
@@ -1,5 +1,5 @@
 (defproject il "0.1.0-SNAPSHOT"
-  :description "Iron Legacy, a browser based sci-fi MMORPG"
+  :description "Iron Legacy, a browser based high-fantasy MMORPG"
   :url "http://example.com/FIXME"
   :license {:name "EPL-2.0 OR GPL-2.0-or-later WITH Classpath-exception-2.0"
             :url "https://www.eclipse.org/legal/epl-2.0/"}
@@ -8,6 +8,7 @@
                  [org.clojure/data.json "2.5.2"]
                  [compojure "1.7.2"]
                  [hiccup "2.0.0"]
+                 [metosin/jsonista "1.0.0"]
                  [org.slf4j/slf4j-simple "2.0.16"]
                  [org.clojure/data.json "2.5.2"]
                  [ring/ring-core "1.15.4"]
diff --git a/shadow-cljs.edn b/shadow-cljs.edn
index 733955d..e7c0538 100644
--- a/shadow-cljs.edn
+++ b/shadow-cljs.edn
@@ -1,5 +1,5 @@
 {:source-paths ["src"]
- :dependencies []
+ :dependencies [[org.clojure/core.async "1.9.865"]]
  :builds
  {:app
   {:target     :browser
diff --git a/src/frontend/il/app.cljs b/src/frontend/il/app.cljs
index a81ae75..61fadcd 100644
--- a/src/frontend/il/app.cljs
+++ b/src/frontend/il/app.cljs
@@ -3,6 +3,9 @@
    [clojure.string :as str]
    ["pixi.js" :as pixi]
    [goog.dom :as dom]
+   [cljs.core.async :as async :refer [go go-loop <! >!]]
+   [il.common.race :as race]
+   [il.common.class :as class]
    [frontend.il.entity :as entity]
    [frontend.il.update :as update]))
 
@@ -31,16 +34,28 @@
   (js/window.addEventListener "keydown" (partial handle-key state velocity-for-key-down))
   (js/window.addEventListener "keyup" (partial handle-key state (fn [_] 0))))
 
-(defn ticker [app state layers entity-id t]
+(defn- drain-outbox! [{:keys [outbox] :as state} tx-chan]
+  (println "Draining outbox: " outbox)
+  (when (count outbox)
+    (go
+      (doseq [msg outbox]
+        (println "Writing event: " msg)
+        (>! tx-chan (js/JSON.stringify (clj->js msg))))))
+  (assoc state :outbox []))
+
+(defn ticker [app state layers entity-id rx-chan tx-chan t]
   (let [dt (.-deltaTime t)
         {world-layer :world-layer
          entity-layer :entity-layer} layers
         global-mouse-pos (.. app -renderer -events -pointer -global)
         entity-relative-mouse-pos (.toLocal ^js entity-layer global-mouse-pos)
-        _ (println @state)
-        {:keys [player entities]} (-> @state
+        send-interval 25 ; Send every 25ms (10 tps)
+        elapsed (.-elapsedMS t)
+        {:keys [player entities]} (-> (update @state :elapsed + elapsed)
                                       (update/update-entities dt layers)
-                                      (update/update-player dt layers entity-id entity-relative-mouse-pos)
+                                      (update/update-player dt send-interval layers entity-id entity-relative-mouse-pos)
+                                      (update/update-from-server rx-chan)
+                                      (drain-outbox! tx-chan)
                                       (->> (swap! state merge)))
         sx (- (/ (.. app -screen -width) 2) (player :x))
         sy (- (/ (.. app -screen -height) 2) (player :y))
@@ -67,29 +82,38 @@
         state (atom {:player {:velocity {:x 0 :y 0}
                               :keymap {:w 0 :a 0 :s 0 :d 0 :lmb 0}
                               :last-attack -1
-                              :attack-speed 666
-                              :meta {:type "player"
-                                     :name "Player"
-                                     :race "Human"
-                                     :class "Priest"}
+                              :attack-speed 0.66
+                              :meta {:name "Player"
+                                     :race race/human
+                                     :class class/priest}
                               :sprite "https://pixijs.com/assets/bunny.png"
                               :speed 10
                               :renderable nil}
-                     :entities {(-> entity-id (swap! inc) (keyword)) {:x 500 :y 500 :sprite "https://pixijs.com/assets/bunny.png"}}})
+                     :elapsed 0
+                     :outbox []
+                     :entities {}})
         width (.-width js/window.screen)
         height (.-height js/window.screen)
         stage (.-stage app)
         world-layer (pixi/Container.)
         entity-layer (pixi/Container.)
         ui-layer (pixi/Container.)
+        tx-chan (async/chan (async/sliding-buffer 10))
+        rx-chan (async/chan (async/sliding-buffer 2))
         layers {:entity-layer entity-layer
                 :world-layer world-layer
                 :ui-layer ui-layer}
         websocket (doto (js/WebSocket. (str "ws://" js/location.host "/ws"))
-                    (.addEventListener "open" #(println "Websocket opened."))
-                    (.addEventListener "message" #(println "Received message​ " (.-data %)))
+                    (.addEventListener "open" #(go-loop []
+                                                 (js/console.log %)
+                                                 (when-let [msg (<! tx-chan)]
+                                                   (.send (.-target %) msg)
+                                                   (recur))))
+                    (.addEventListener "message" #(async/put! rx-chan (-> %
+                                                                          (.-data)
+                                                                          (js/JSON.parse)
+                                                                          (js->clj :keywordize-keys true))))
                     (.addEventListener "close" #(println "Websocket closed.")))]
-
     (.. app
         (init #js {:width width :height height :backgroundColor 0x222})
         (then (fn [_]
@@ -110,4 +134,4 @@
                           (partial sb-callback false))
                       player (assoc e :renderable p :shootbox sb)]
                   (swap! state update-in [:player] merge player)
-                  (.. app -ticker (add (partial ticker app state layers entity-id)))))))))
+                  (.. app -ticker (add (partial ticker app state layers entity-id rx-chan tx-chan)))))))))
diff --git a/src/frontend/il/update.cljs b/src/frontend/il/update.cljs
index 4f20f39..d9d31f4 100644
--- a/src/frontend/il/update.cljs
+++ b/src/frontend/il/update.cljs
@@ -1,6 +1,7 @@
 (ns frontend.il.update
   (:require
-   [frontend.il.entity :as entity]))
+   [frontend.il.entity :as entity]
+   [cljs.core.async :as async]))
 
 (defn apply-velocity [e dt]
   (if (contains? e :velocity)
@@ -21,7 +22,7 @@
 (defn apply-player-shoot [state entity-id mouse-pos]
   (if (and (get-in state [:player :keymap :lmb] false)
            (< (+ (get-in state [:player :last-attack] -1)
-                 (get-in state [:player :attack-speed] 888))
+                 (* 1000 (get-in state [:player :attack-speed] 0.75)))
               (js/Date.now)))
     (let [player-sprite (get-in state [:player :renderable])
           speed 15
@@ -36,17 +37,31 @@
           h (js/Math.sqrt (+ (* dx dx) (* dy dy)))
           vx (* (/ dx h) speed)
           vy (* (/ dy h) speed)
-          eid (swap! entity-id inc)
+          eid (-> (swap! entity-id inc)
+                  (str)
+                  (keyword))
           e {:sprite image
-             :hyp h
+             :hypotenuse h
              :x start-x
              :y start-y
              :velocity {:x vx :y vy}}]
       (-> state
-          (assoc-in [:entities (keyword (str eid))] e)
+          (update :outbox conj {:type "shoot"})
+          (assoc-in [:entities eid] e)
           (assoc-in [:player :last-attack] (js/Date.now))))
     state))
 
+(defn apply-player-position [state send-interval]
+  (let [{elapsed :elapsed
+         {x :x y :y lx :last-x ly :last-y} :player} state]
+    (if (and (>= elapsed send-interval)
+             (not (and (= lx x) (= ly y))))
+      (-> state
+          (assoc :elapsed (mod elapsed send-interval))
+          (update :player assoc :last-x x :last-y y)
+          (update :outbox conj {:type "position" :x x :y y}))
+      state)))
+
 (defn update-entities [state dt layers]
   (let [{entities :entities} state
         new-entities (update-vals entities #(-> %
@@ -54,10 +69,25 @@
                                                 (apply-velocity dt)))]
     (assoc state :entities new-entities)))
 
-(defn update-player [state dt layers entity-id mouse-pos]
+(defn update-player [state dt send-interval layers entity-id mouse-pos]
   (let [{player :player} state
         updated-player (-> player
                            (apply-renderable layers)
                            (apply-velocity dt))]
     (-> (assoc state :player updated-player)
+        (apply-player-position send-interval)
         (apply-player-shoot entity-id mouse-pos))))
+
+(defn- deep-merge [a b]
+  (if (and (map? a) (map? b))
+    (merge-with deep-merge a b)
+    b))
+
+(defn update-from-server [state rx-chan]
+  (loop [state-acc state
+         {:keys [kind] :as msg} (async/poll! rx-chan)]
+    (if (and msg (= kind "sync"))
+      (recur
+       (deep-merge state-acc msg)
+       (async/poll! rx-chan))
+      state-acc)))
diff --git a/src/il/class.clj b/src/il/class.clj
deleted file mode 100644
index 927ac3f..0000000
--- a/src/il/class.clj
+++ /dev/null
@@ -1,24 +0,0 @@
-(ns il.class)
-
-(def priest {:name "priest"
-             :stats { :atkspeed 0.5 }})
-(def warden "warden")
-(def sorcerer "sorcerer")
-(def magician "magician")
-(def thief "thief")
-(def ranger "ranger")
-(def artificer "artificer")
-(def corsair "corsair")
-(def astromancer "astromancer")
-
-(def valid-class? [class]
-  (let [classes [priest
-                 warden
-                 sorcerer
-                 magician
-                 thief
-                 ranger
-                 artificer
-                 corsair
-                 astromancer]]
-    (contains? classes class)))
diff --git a/src/il/common/class.cljc b/src/il/common/class.cljc
new file mode 100644
index 0000000..b34b28b
--- /dev/null
+++ b/src/il/common/class.cljc
@@ -0,0 +1,33 @@
+(ns il.common.class)
+
+(def priest {:name "priest"
+             :stats {:hp 90}})
+(def warden {:name "priest"
+             :stats {:hp 120}})
+(def sorcerer {:name "sorcerer"
+               :stats {:hp 90}})
+(def magician {:name "magician"
+               :stats {:hp 80}})
+(def thief {:name "thief"
+            :stats {:hp 80}})
+(def ranger {:name "ranger"
+             :stats {:hp 80}})
+(def artificer {:name "artificer"
+                :stats {:hp 90}})
+(def corsair {:name "corsair"
+              :stats {:hp 80}})
+(def astromancer {:name "astromancer"
+                  :stats {:hp 100}})
+
+(def all [priest
+          warden
+          sorcerer
+          magician
+          thief
+          ranger
+          artificer
+          corsair
+          astromancer])
+
+(defn valid-class? [c]
+  (some #{c} (map :name all)))
diff --git a/src/il/common/race.cljc b/src/il/common/race.cljc
new file mode 100644
index 0000000..e228493
--- /dev/null
+++ b/src/il/common/race.cljc
@@ -0,0 +1,3 @@
+(ns il.common.race)
+
+(def human "human")
diff --git a/src/il/core.clj b/src/il/core.clj
index 4709ddf..15376bc 100644
--- a/src/il/core.clj
+++ b/src/il/core.clj
@@ -3,24 +3,31 @@
             [ring.websocket.async :refer [go-websocket]]
             [compojure.core :as c]
             [compojure.route :as route]
-            [clojure.core.async :refer [<! >! go-loop]]
-            [clojure.data.json :as json]
-            [hiccup.core :as h]))
+            [clojure.core.async :as async :refer [<! >! go-loop]]
+            [hiccup.core :as h]
+            [il.state :as s]
+            [il.json :as j]
+            [il.handler :as handler]))
 
-(defn ws-handler [_]
+(defn ws-handler [state state-chan player-id]
   (go-websocket [in out err]
+                (s/change state-chan update :players assoc player-id {:out out :in in :err err})
                 (go-loop []
                   (when-let [e (<! err)]
                     (println (.getMessage e))
                     (recur)))
                 (go-loop []
-                  (if-let [msg (<! in)]
-                    (do
+                  (if-let [raw (<! in)]
+                    (let [msg (j/from-json raw)
+                          type (get msg :type "invalid")]
                       (cond
-                        (= msg "world") (>! out "Hello World!"))
+                        (= type "shoot") (handler/handle-shoot state state-chan player-id msg)
+                        (= type "invalid") (>! out "Hello World!"))
                       (println msg)
                       (recur))
-                    (println "Closed.")))))
+                    (do
+                      (s/change state-chan update :players dissoc player-id)
+                      (println "Closed: " player-id))))))
 
 (defn index-handler [_]
   (h/html
@@ -32,14 +39,42 @@
      [:script {:src "/js/app.js" :defer true}]]
     [:body]]))
 
-(c/defroutes app
-  (c/GET "/" r (index-handler r))
-  (c/GET "/ws" r (ws-handler r))
-  (route/resources "/")
-  (route/not-found "<h1>The requested resource does not exist...</h1>"))
+(defn build-application [state state-chan]
+  (c/routes
+   (c/GET "/" r (index-handler r))
+   (c/GET "/ws" [] (ws-handler @state state-chan (random-uuid))) ; TODO: Auth here
+   (route/resources "/")
+   (route/not-found "<h1>The requested resource does not exist...</h1>")))
+
+(defn game-loop [state state-chan]
+  (go-loop []
+    (let [start-time (System/currentTimeMillis)
+          max-inputs-per-tick 15000 ; Stops the game from spinning endlessly, dropping ticks
+          events-to-apply (loop [inputs []
+                                 count 0]
+                            (if (>= count max-inputs-per-tick)
+                              inputs
+                              (if-let [args (async/poll! state-chan)]
+                                (recur (conj inputs args) (inc count))
+                                inputs)))]
+      (doseq [event-args events-to-apply]
+        (apply swap! state event-args))
+      (doseq [{out :out} (vals (:players @state))]
+        (>! out (j/to-json {:type "sync"
+                            :entities (:entities @state)})))
+      (let [elapsed (- (System/currentTimeMillis) start-time)
+            sleep-time (max 0 (- 50 elapsed))]
+        (<! (async/timeout sleep-time))))
+    (recur)))
 
 (defn -main []
-  (let [port 5000]
-    (jetty/run-jetty
-     app
-     {:port port :join? true :max-idle-timeout 60000}))) ; Allow 60 second idle on websockets
+  (let [state (atom {:systems    []
+                     :entities   {}
+                     :players    {}})
+        state-chan (async/chan)
+        app (build-application state state-chan)]
+    (game-loop state state-chan)
+    (let [port 5000]
+      (jetty/run-jetty
+       app
+       {:port port :join? true :max-idle-timeout 60000})))) ; Allow 60 second idle on websockets
diff --git a/src/il/handler.clj b/src/il/handler.clj
new file mode 100644
index 0000000..6f0c42e
--- /dev/null
+++ b/src/il/handler.clj
@@ -0,0 +1,18 @@
+(ns il.handler
+  (:require [il.state :as s]))
+
+(defn handle-shoot [state state-chan player-id msg]
+  (let [bullet-id (random-uuid)
+        {x :x y :y} (get-in state [:players player-id])
+        {tx :x ty :y} msg
+        dx (- tx x)
+        dy (- ty y)
+        h (Math/sqrt (+ (Math/pow dx 2) (Math/pow dy 2)))
+        speed 15 ; TODO: Calculate projectile speed based on player stats
+        vx (* (/ dx h) speed)
+        vy (* (/ dy h) speed)
+        bullet {:sprite "/sprite/projectile.png" ; TODO: Render sprite based on player weapon
+                :x x
+                :y y
+                :velocity {:x vx :y vy}}]
+    (s/change state-chan update :entities assoc bullet-id bullet)))
diff --git a/src/il/json.clj b/src/il/json.clj
new file mode 100644
index 0000000..ec30158
--- /dev/null
+++ b/src/il/json.clj
@@ -0,0 +1,10 @@
+(ns il.json
+  (:require [jsonista.core :as j]))
+
+(def keyword-mapper (j/object-mapper {:decode-key-fn true}))
+
+(defn from-json [str]
+  (j/read-value str keyword-mapper))
+
+(defn to-json [data]
+  (j/write-value-as-string data))
diff --git a/src/il/state.clj b/src/il/state.clj
new file mode 100644
index 0000000..23d44aa
--- /dev/null
+++ b/src/il/state.clj
@@ -0,0 +1,5 @@
+(ns il.state
+  (:require [clojure.core.async :refer [>! go]]))
+
+(defn change [state-chan & args]
+  (go (>! state-chan args)))