use KEYUP instead of KEYDOWN because otherwise switching from beamer mode does not work

gauss-turing/webserver/gauss_turing.py

@@ -371,7 +371,7 @@ class Game:
             pygame.time.wait(1500)
             self.state = 'reset'
 
-        pygame.display.update()
+        pygame.display.flip()
 
     def process_inputs(self):
         # proceed events
@@ -400,7 +400,7 @@ class Game:
                         self.state = 'input'
                     elif self.state == 'input':
                         self.state = 'running'
-            elif event.type == pygame.KEYDOWN:
+            elif event.type == pygame.KEYUP:
                 if event.key == pygame.K_x:
                     if not self.beamer_mode:
                         # switch to beamer mode