--- atanks-4.3.old/src/atanks.cpp
+++ atanks-4.3/src/atanks.cpp
@@ -518,6 +518,12 @@
   return (0);
 }
 
+void handle_close (void)
+{
+    allegro_exit();
+    exit (1);
+}
+
 ENVIRONMENT *init_game_settings (GLOBALDATA *global)
 {
   int count, x, y, z;
@@ -576,6 +582,8 @@
     set_display_switch_mode(SWITCH_BACKGROUND);
 #endif
 
+  set_close_button_callback (handle_close);
+
   if (install_keyboard () < 0)
     {
       perror ( "install_keyboard failed");