diff --git a/.dir-locals.el b/.dir-locals.el
index 273bf42..2351726 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -6,10 +6,11 @@
  (nil
   . ((eval
       . (progn
-          (unless (fboundp 'clj-watch)
-            (load (expand-file-name
-                   "watch.el"
-                   (locate-dominating-file default-directory ".dir-locals.el"))))
+          (let ((root (locate-dominating-file default-directory ".dir-locals.el")))
+            (unless (fboundp 'clj-watch)
+              (load (expand-file-name "watch.el" root)))
+            (unless (fboundp 'clj-game-throw-last-error)
+              (load (expand-file-name "cider-error.el" root))))
 
           (defun clj-game-run-main ()
             "Send (future (-main)) to the REPL."
@@ -33,6 +34,7 @@
                 (define-key m (kbd "C-c g r") #'clj-game-run-main)
                 (define-key m (kbd "C-c g e") #'clj-game-clear-error)
                 (define-key m (kbd "C-c g c") #'clj-game-reload-config)
+                (define-key m (kbd "C-c g x") #'clj-game-throw-last-error)
                 m)))
 
           (unless (fboundp 'clj-game-mode)
diff --git a/src/engine.clj b/src/engine.clj
index 2425d43..d9e5610 100644
--- a/src/engine.clj
+++ b/src/engine.clj
@@ -8,6 +8,15 @@
 (defonce ^:private game-state (atom nil))
 (defonce ^:private game-config (atom nil))
 
+(defn report-exception!
+  "Stash the exception and print a marker line. Emacs watches the REPL output
+  for the marker and rethrows the stashed exception over nREPL, so it lands in
+  cider's stacktrace buffer instead of as an unreadable println. See
+  cider-error.el."
+  [^Throwable t]
+  (reset! last-error t)
+  (println "SIAM-REPORT-EXCEPTION"))
+
 (defn clear-error! []
   (reset! last-error nil))
 
@@ -25,15 +34,17 @@
     (do
       (rl/set-trace-log-level! rl/log-warning)
       (rl/init-window! width height title)
-      (rl/set-target-fps! 60)
+      (rl/set-target-fps! 30)
       (let [config (if config-path
                      (edn/read-string (slurp config-path))
                      {})]
         (reset! game-config {:config-path config-path :config config})
+        ;; TODO: We should actually not commit until the frame is complete, because if not we will re-enter
+        ;; input and call it several times if update or draw throw
         (try
           (reset! game-state (init config))
           (catch Throwable t
-            (println t)))
+            (report-exception! t)))
         (while (not (rl/window-should-close?))
           (if @last-error
             (Thread/sleep 50)
@@ -45,14 +56,13 @@
                   (draw config @game-state)
                   (w/watch! (watch-fn config @game-state))
                   (catch Throwable t
-                    (println t)
-                    (reset! last-error t)
+                    (report-exception! t)
                     (w/watch! (merge (watch-fn config @game-state) {:error t}))))))))
         (try
           (when unload
             (unload @game-state))
           (catch Throwable t
-            (println t)))
+            (report-exception! t)))
         (rl/close-window!)
         (reset! last-error nil)
         (reset! game-state nil)