diff --git a/src/clj/byf/api.clj b/src/clj/byf/api.clj
index 2b98380..4ab4795 100644
--- a/src/clj/byf/api.clj
+++ b/src/clj/byf/api.clj
@@ -40,11 +40,16 @@
   [{:keys [params]}]
   (notifications/notify-slack "A new game was added!")
   (let [validated (validate/conform-data :game params)
-        game-id (db/add-game! validated)]
+        last-game (-> (db/query db/last-game-sql)
+                      first)]
+    (if (or
+         (:force validated)
+         (not (games/equal? validated last-game)))
 
-    (as-json
-     (resp/created "/api/games"
-                   {:id game-id}))))
+      (as-json
+       (resp/created "/api/games"
+                     {:id  (db/add-game! (dissoc validated :force))}))
+      (resp/bad-request "Duplicate game"))))
 
 (defn add-player!
   "Adds a new user to the platform, authenticated with basic Auth"
diff --git a/src/clj/byf/db.clj b/src/clj/byf/db.clj
index c1c7f67..5152e34 100644
--- a/src/clj/byf/db.clj
+++ b/src/clj/byf/db.clj
@@ -70,6 +70,13 @@
       (h/from :league)
       (h/where [:= :id league-id])))
 
+(defn last-game-sql
+  []
+  (-> (h/select :*)
+      (h/from :game)
+      (h/order-by [:played_at :desc])
+      (h/limit 1)))
+
 (defn query
   [func & args]
   (jdbc/query (db-spec)
diff --git a/src/cljc/byf/games.cljc b/src/cljc/byf/games.cljc
index 561771e..d3d1b9f 100644
--- a/src/cljc/byf/games.cljc
+++ b/src/cljc/byf/games.cljc
@@ -155,3 +155,23 @@
         (if (>= next prev)
           (recur rst (+ curr-increase (- next prev)) new-max)
           (recur rst 0 new-max))))))
+
+(defn invert-game
+  [game]
+  (-> game
+      (assoc :p1 (:p2 game))
+      (assoc :p2 (:p1 game))
+      (assoc :p1_points (:p2_points game))
+      (assoc :p2_points (:p1_points game))
+      (assoc :p1_using (:p2_using game))
+      (assoc :p2_using (:p1_using game))))
+
+(defn equal?
+  [g1 g2]
+  (let [useful #(select-keys % [:p1 :p2 :p1_points :p2_points :p1_using :p2_using])
+        g1_ (useful g1)
+        g2_ (useful g2)
+        g2_inv (invert-game g2_)]
+
+    (or (= g1_ g2_)
+        (= g1_ g2_inv))))
diff --git a/src/cljs/byf/common/handlers.cljs b/src/cljs/byf/common/handlers.cljs
index 9aee049..5d6bb96 100644
--- a/src/cljs/byf/common/handlers.cljs
+++ b/src/cljs/byf/common/handlers.cljs
@@ -58,18 +58,19 @@
                   :on-failure [:failed]}}))
 
 (defn writer
-  [page uri on-success transform-params-fn]
-  (fn [{:keys [db]} _]
-    {:db db
-     :http-xhrio {:method :post
-                  :uri uri
-                  :params (merge (transform-params-fn db)
-                                 {:league_id (get-league-id db)})
-
-                  :format (ajax/json-request-format)
-                  :response-format (ajax/json-response-format {:keywords? true})
-                  :on-success [on-success]
-                  :on-failure [:failed]}}))
+  ([page uri on-success transform-params-fn]
+   (writer page uri on-success transform-params-fn :failed))
+  ([page uri on-success transform-params-fn on-failure]
+   (fn [{:keys [db]} _]
+     {:http-xhrio {:method :post
+                   :uri uri
+                   :params (merge (transform-params-fn db)
+                                  {:league_id (get-league-id db)})
+
+                   :format (ajax/json-request-format)
+                   :response-format (ajax/json-response-format {:keywords? true})
+                   :on-success [on-success]
+                   :on-failure [on-failure]}})))
 
 (defn failed
   [page]
diff --git a/src/cljs/byf/league_detail/handlers.cljs b/src/cljs/byf/league_detail/handlers.cljs
index 132cc9f..b8043a5 100644
--- a/src/cljs/byf/league_detail/handlers.cljs
+++ b/src/cljs/byf/league_detail/handlers.cljs
@@ -45,7 +45,7 @@
    :league_id nil
    :show-all? false
    :game-config shared/default-game-config
-   :show-notification false
+   :notification nil
    :loading? false
    :show-graph false})
 
@@ -63,14 +63,18 @@
   [name-mapping vals]
   (medley/map-keys #(get name-mapping %) vals))
 
-(rf/reg-sub ::show-notification (getter [:show-notification]))
-(rf/reg-event-db ::show-notification
-                 (fn [db _]
-                   (common/assoc-in* db page [:show-notification] true)))
+(rf/reg-sub ::notification (getter [:notification]))
+(rf/reg-event-db ::notification
+                 (fn [db [_ type msg]]
+                   (common/assoc-in* db
+                                     page
+                                     [:notification]
+                                     {:type type
+                                      :msg msg})))
 
 (rf/reg-event-db ::clear-notification
                  (fn [db _]
-                   (common/assoc-in* db page [:show-notification] false)))
+                   (common/assoc-in* db page [:notification] false)))
 
 (rf/reg-sub ::show-graph (getter [:show-graph]))
 (rf/reg-sub ::loading? (getter [:loading?]))
@@ -258,14 +262,20 @@
 (rf/reg-event-db ::played_at (setter [:game :played_at]))
 
 (defn- reload-fn-gen
-  [extra-signal]
-  (fn [{:keys [db]} _]
-    {:db db
-     :dispatch-n (cons extra-signal [[::show-notification]
-                                     [::players-handlers/load-players]
-                                     [::load-games]])}))
+  [{:keys [db] :as full} other]
+  (js/console.log "Other = " other ", full = " full)
+  {:db db
+   :dispatch-n [[::notification :success "Game added successfully"]
+                [::reset-game]
+                [::players-handlers/load-players]
+                [::load-games]]})
+
+(rf/reg-event-fx ::add-game-success reload-fn-gen)
 
-(rf/reg-event-fx ::add-game-success (reload-fn-gen [::reset-game]))
+(rf/reg-event-fx ::add-game-failed
+                 (fn [{:keys [db]}]
+                   (js/console.log "inside game failed")
+                   {:dispatch [::notification :failure "Duplicate game"]}))
 
 (rf/reg-event-db ::failed (common/failed page))
 
@@ -289,7 +299,9 @@
 
 (rf/reg-event-fx ::add-game
                  (common/writer page "/api/add-game"
-                                ::add-game-success game-transform))
+                                ::add-game-success
+                                game-transform
+                                ::add-game-failed))
 
 (rf/reg-sub ::hidden? (sets/in? page :hidden-players))
 
diff --git a/src/cljs/byf/league_detail/views.cljs b/src/cljs/byf/league_detail/views.cljs
index 0b3ca59..4b15966 100644
--- a/src/cljs/byf/league_detail/views.cljs
+++ b/src/cljs/byf/league_detail/views.cljs
@@ -428,13 +428,18 @@
 
 (defn notifications
   []
-  (let [show-notification (rf/subscribe [::handlers/show-notification])]
+  (let [notification (rf/subscribe [::handlers/notification])]
     (fn []
-      (when @show-notification
-        [:div.notification.is-success
+      (when @notification
+        [:div.notification
+         {:class (case (:type @notification)
+                   :success "is-success"
+                   :failure "is-failure")}
+
+
          [:button.delete
           {:on-click #(rf/dispatch [::handlers/clear-notification])}]
-         "Thank you, your game has been recorded"]))))
+         (:msg @notification)]))))
 
 (defn root
   []
diff --git a/test/clj/byf/api_test.clj b/test/clj/byf/api_test.clj
index 3ebc888..f1d5d04 100644
--- a/test/clj/byf/api_test.clj
+++ b/test/clj/byf/api_test.clj
@@ -6,6 +6,7 @@
             [clojure.test :refer [deftest is testing use-fixtures join-fixtures]]
             [byf.api :as sut]
             [byf.db :as db]
+            [byf.games :refer [invert-game]]
             [environ.core :refer [env]]
             [ring.mock.request :as mock])
   (:import (java.util UUID)))
@@ -58,7 +59,7 @@
             authenticated-req
             sut/app)]
 
-    (assert (contains? #{201 401} status), "Invalid status code")
+    (assert (contains? #{201 401 400} status), "Invalid status code")
     response))
 
 (defn- store-users!
@@ -70,6 +71,28 @@
 
     [p1-id p2-id]))
 
+(deftest store-results-invariants-test
+  (testing "Can't add two equal games"
+    (let [[p1-id p2-id] (store-users!)
+          game1 {:p1 (:player-id p1-id)
+                 :p2 (:player-id p2-id)
+                 :league_id sample-league-id
+                 :p1_using "RM"
+                 :p2_using "Juv"
+                 :p1_points 3
+                 :p2_points 0
+                 :played_at "2018-08-29+01:0021:50:32"}
+          game2 (invert-game game1)
+          game3 (assoc game2 :force true)]
+
+      (let [first-call (write-api-call "/add-game" game1)
+            second-call (write-api-call "/add-game" game2)
+            third-call (write-api-call "/add-game" game3)]
+
+        (is (= 201 (:status first-call)))
+        (is (= 400 (:status second-call)))
+        (is (= 201 (:status third-call)))))))
+
 (deftest store-results-test
   (testing "Should be able to store results"
     (let [[p1-id p2-id] (store-users!)
@@ -80,28 +103,26 @@
                   :p2_using "Juv"
                   :p1_points 3
                   :p2_points 0
-                  :played_at "2018-08-29+01:0021:50:32"}
-
-          _ (write-api-call "/add-game" sample)
-          games (read-api-call "/api/games" {:league_id sample-league-id})
-
-          desired {"p1" (str (:player-id p1-id))
-                   "p1_points" 3,
-                   "p1_using" "RM",
-                   "p2" (str (:player-id p2-id)),
-                   "p2_points" 0,
-                   "p2_using" "Juv"
-                   "played_at" "2018-08-29T20:50:00Z"}]
-
-      (is (= 200 (:status games)))
-
-      (is (= desired
-             (select-keys
-              (first (json/read-str (:body games)))
-              ["p1_points" "p2_points"
-               "p1" "p2"
-               "p1_using" "p2_using"
-               "played_at"]))))))
+                  :played_at "2018-08-29+01:0021:50:32"}]
+      (write-api-call "/add-game" sample)
+      (let [games (read-api-call "/api/games" {:league_id sample-league-id})
+            desired {"p1" (str (:player-id p1-id))
+                     "p1_points" 3,
+                     "p1_using" "RM",
+                     "p2" (str (:player-id p2-id)),
+                     "p2_points" 0,
+                     "p2_using" "Juv"
+                     "played_at" "2018-08-29T20:50:00Z"}]
+
+        (is (= 200 (:status games)))
+
+        (is (= desired
+               (select-keys
+                (first (json/read-str (:body games)))
+                ["p1_points" "p2_points"
+                 "p1" "p2"
+                 "p1_using" "p2_using"
+                 "played_at"])))))))
 
 (deftest get-players-test
   (testing "Fetching all the existing players"