diff -ruN a/hexoshi.py b/hexoshi.py
--- a/hexoshi.py
+++ b/hexoshi.py
@@ -19,6 +19,8 @@
 __version__ = "0.3a0"
 
 
+import pygame
+import asyncio
 import argparse
 import datetime
 import gettext
@@ -48,6 +50,10 @@
     __file__ = sys.executable
 
 hlib.datadir = os.path.join(os.path.dirname(__file__), "data")
+if os.path.isdir("/saves"):
+    # On the web the page keeps /saves in the browser (IndexedDB).
+    hlib.configdir = "/saves/hexoshi/config"
+    hlib.localdir = "/saves/hexoshi/local"
 
 gettext.install("hexoshi", os.path.abspath(os.path.join(hlib.datadir, "locale")))
 
@@ -108,7 +114,8 @@
     help=_("Quit immediately on startup (useful with -m or -s)."),
     action="store_true")
 parser.add_argument("--god")
-args = parser.parse_args()
+# The web player has no command line; the build runs this with -m -q to make the map.
+args = parser.parse_args(os.environ.get("HEXOSHI_ARGS", "-p").split())
 
 PRINT_ERRORS = args.print_errors
 DELTA = not args.nodelta
@@ -185,10 +192,10 @@
                     print(_("Invalid cheat code: {}").format(self.cheatcode))
 
     def event_close(self):
-        self.end()
+        pass
 
     def event_paused_close(self):
-        self.event_close()
+        pass
 
 
 class Level(sge.dsp.Room):
@@ -4438,14 +4445,17 @@
         y = get_yregion(self.image_ycenter)
         i = (sge.game.current_room.fname, self.spawn_id, x, y)
         dlg = TeleportDialog(i)
-        dlg.show()
-        if dlg.selection and dlg.selection != i:
-            other.x = self.image_xcenter
-            other.bbox_bottom = self.image_top
-            other.warp_dest = "{}:{}".format(*dlg.selection[:2])
-            other.warp_out()
-            play_sound(hlib.teleport_sound, self.image_xcenter,
-                       self.image_ycenter)
+
+        def teleport_done():
+            if dlg.selection and dlg.selection != i:
+                other.x = self.image_xcenter
+                other.bbox_bottom = self.image_top
+                other.warp_dest = "{}:{}".format(*dlg.selection[:2])
+                other.warp_out()
+                play_sound(hlib.teleport_sound, self.image_xcenter,
+                           self.image_ycenter)
+
+        dlg.show(on_close=teleport_done)
 
     def create_children(self):
         self.created = True
@@ -4868,8 +4878,7 @@
 
 class MainMenu(Menu):
 
-    items = [_("New Game"), _("Load Game"), _("Options"), _("Credits"),
-             _("Quit")]
+    items = [_("New Game"), _("Load Game"), _("Options"), _("Credits")]
 
     def event_choose(self):
         if self.choice == 0:
@@ -4885,8 +4894,6 @@
             credits_room = CreditsScreen.load(os.path.join("special",
                                                            "credits.json"))
             credits_room.start()
-        else:
-            sge.game.end()
 
 
 class NewGameMenu(Menu):
@@ -4986,7 +4993,6 @@
     def create_page(cls, default=0):
         smt = hlib.scale_method if hlib.scale_method else "fastest"
         cls.items = [
-            _("Fullscreen: {}").format(_("On") if hlib.fullscreen else _("Off")),
             _("Scale Method: {}").format(smt),
             _("Sound Volume: {}%").format(int(hlib.sound_volume * 100)),
             _("Music Volume: {}%").format(int(hlib.music_volume * 100)),
@@ -4996,7 +5002,9 @@
             _("Joystick Threshold: {}%").format(int(hlib.joystick_threshold * 100)),
             _("Configure keyboard"), _("Configure joysticks"),
             _("Detect joysticks"), _("Back")]
-        return cls.create(default)
+        # The list lost its first entry (fullscreen): the numbers used by
+        # event_choose still count it, so the default shifts by one.
+        return cls.create(max(default - 1, 0))
 
     def event_press_left(self):
         # Variant of event_press_enter which passes True to the custom
@@ -5014,12 +5022,9 @@
         self.event_press_enter()
 
     def event_choose(self, left=False):
-        if self.choice == 0:
-            play_sound(hlib.select_sound)
-            hlib.fullscreen = not hlib.fullscreen
-            hlib.game.update_fullscreen()
-            OptionsMenu.create_page(default=self.choice)
-        elif self.choice == 1:
+        if self.choice is not None:
+            self.choice += 1  # see create_page
+        if self.choice == 1:
             choices = [None, "noblur", "smooth"] + sge.SCALE_METHODS
             if hlib.scale_method in choices:
                 i = choices.index(hlib.scale_method)
@@ -5146,102 +5151,41 @@
         text = _("Press the key you wish to bind to this function, or the "
                  "Escape key to cancel.")
 
+        def bound(target, self=self, default=self.choice):
+            # What to do with the key picked (None: cancelled).
+            def done(k):
+                if k is not None:
+                    bind_key(target, k)
+                    play_sound(hlib.confirm_sound)
+                else:
+                    play_sound(hlib.cancel_sound)
+                self.__class__.create_page(default=default)
+            return done
+
         if self.choice == 0:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.left_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.left_key))
         elif self.choice == 1:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.right_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.right_key))
         elif self.choice == 2:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.up_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.up_key))
         elif self.choice == 3:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.down_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.down_key))
         elif self.choice == 4:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.jump_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.jump_key))
         elif self.choice == 5:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.shoot_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.shoot_key))
         elif self.choice == 6:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.secondary_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.secondary_key))
         elif self.choice == 7:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.aim_diag_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.aim_diag_key))
         elif self.choice == 8:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.aim_up_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.aim_up_key))
         elif self.choice == 9:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.aim_down_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.aim_down_key))
         elif self.choice == 10:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.pause_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.pause_key))
         elif self.choice == 11:
-            k = wait_key(text)
-            if k is not None:
-                bind_key(hlib.map_key, k)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_key(text, bound(hlib.map_key))
         else:
             play_sound(hlib.cancel_sound)
             OptionsMenu.create_page(default=5)
@@ -5295,102 +5239,41 @@
         text = _("Press the joystick button, axis, or hat direction you wish "
                  "to bind to this function, or the Escape key to cancel.")
 
+        def bound(target, self=self, default=self.choice):
+            # What to do with the joystick input picked (None: cancelled).
+            def done(js):
+                if js is not None:
+                    bind_js(target, js)
+                    play_sound(hlib.confirm_sound)
+                else:
+                    play_sound(hlib.cancel_sound)
+                self.__class__.create_page(default=default)
+            return done
+
         if self.choice == 0:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.left_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.left_js))
         elif self.choice == 1:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.right_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.right_js))
         elif self.choice == 2:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.up_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.up_js))
         elif self.choice == 3:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.down_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.down_js))
         elif self.choice == 4:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.jump_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.jump_js))
         elif self.choice == 5:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.shoot_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.shoot_js))
         elif self.choice == 6:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.secondary_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.secondary_js))
         elif self.choice == 7:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.aim_diag_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.aim_diag_js))
         elif self.choice == 8:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.aim_up_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.aim_up_js))
         elif self.choice == 9:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.aim_down_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.aim_down_js))
         elif self.choice == 10:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.pause_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.pause_js))
         elif self.choice == 11:
-            js = wait_js(text)
-            if js is not None:
-                bind_js(hlib.map_js, js)
-                play_sound(hlib.confirm_sound)
-            else:
-                play_sound(hlib.cancel_sound)
-            self.__class__.create_page(default=self.choice)
+            wait_js(text, bound(hlib.map_js))
         else:
             play_sound(hlib.cancel_sound)
             OptionsMenu.create_page(default=6)
@@ -5824,74 +5707,51 @@
     xsge_gui.escape_joystick_events = [(0, "button", 8)]
 
 
-def wait_key(text):
-    # Wait for a key press and return it.
-    while True:
-        # Input events
-        sge.game.pump_input()
-        while sge.game.input_events:
-            event = sge.game.input_events.pop(0)
-            if isinstance(event, sge.input.KeyPress):
-                sge.game.pump_input()
-                sge.game.input_events = []
-                if event.key == "escape":
-                    return None
-                else:
-                    return event.key
-
-        # Regulate speed
-        sge.game.regulate_speed(fps=10)
-
-        # Project text
-        sge.game.project_text(hlib.font, text, sge.game.width / 2,
-                              sge.game.height / 2, width=sge.game.width,
-                              height=sge.game.height,
-                              color=sge.gfx.Color("white"),
-                              halign="center", valign="middle",
-                              outline=sge.gfx.Color("black"),
-                              outline_thickness=1)
-
-        # Refresh
-        hlib.game.refresh_screen(0, 0)
+class WaitInputDialog(xsge_gui.Dialog):
 
+    # Waits for a key press (or a joystick event) and keeps it in
+    # ``result`` (None: cancelled with Escape).  It replaces the loops that
+    # wait_key() and wait_js() used to run.
+
+    def __init__(self, text, joystick=False):
+        self.result = None
+        self.joystick = joystick
+        w = sge.game.width
+        h = sge.game.height
+        super().__init__(gui_handler, 0, 0, w, h,
+                         background_color=sge.gfx.Color("black"),
+                         border=False)
+        xsge_gui.Label(self, 0, 0, 0, text, font=hlib.font, width=w, height=h,
+                       color=sge.gfx.Color("white"), halign="center",
+                       valign="middle")
+
+    def event_global_key_press(self, key, char):
+        if self.joystick:
+            if key == "escape":
+                self.destroy()
+        else:
+            self.result = None if key == "escape" else key
+            self.destroy()
 
-def wait_js(text):
-    # Wait for a joystick press and return it.
-    sge.game.pump_input()
-    sge.game.input_events = []
+    def event_global_joystick(self, js_name, js_id, input_type, input_id,
+                              value):
+        if (self.joystick
+                and input_type not in {"axis0", "hat_center_x", "hat_center_y"}
+                and value >= hlib.joystick_threshold):
+            self.result = (js_id, input_type, input_id)
+            self.destroy()
 
-    while True:
-        # Input events
-        sge.game.pump_input()
-        while sge.game.input_events:
-            event = sge.game.input_events.pop(0)
-            if isinstance(event, sge.input.KeyPress):
-                if event.key == "escape":
-                    sge.game.pump_input()
-                    sge.game.input_events = []
-                    return None
-            elif isinstance(event, sge.input.JoystickEvent):
-                if (event.input_type not in {"axis0", "hat_center_x",
-                                             "hat_center_y"}
-                        and event.value >= hlib.joystick_threshold):
-                    sge.game.pump_input()
-                    sge.game.input_events = []
-                    return (event.js_id, event.input_type, event.input_id)
 
-        # Regulate speed
-        sge.game.regulate_speed(fps=10)
+def wait_key(text, callback):
+    # Wait for a key press and pass it to callback (None if cancelled).
+    dialog = WaitInputDialog(text)
+    dialog.show(on_close=lambda: callback(dialog.result))
 
-        # Project text
-        sge.game.project_text(hlib.font, text, sge.game.width / 2,
-                              sge.game.height / 2, width=sge.game.width,
-                              height=sge.game.height,
-                              color=sge.gfx.Color("white"),
-                              halign="center", valign="middle",
-                              outline=sge.gfx.Color("black"),
-                              outline_thickness=1)
 
-        # Refresh
-        hlib.game.refresh_screen(0, 0)
+def wait_js(text, callback):
+    # Wait for a joystick press and pass it to callback (None if cancelled).
+    dialog = WaitInputDialog(text, joystick=True)
+    dialog.show(on_close=lambda: callback(dialog.result))
 
 
 def show_error(message):
@@ -7109,10 +6969,14 @@
 
 print(_("Starting game…"))
 
-try:
-    if not QUIT:
-        sge.game.start()
-    else:
-        print(_("Successfully started Hexoshi. Quitting now as -q was passed."))
-finally:
-    write_to_disk()
+async def main():
+    try:
+        if not QUIT:
+            await sge.game.start()
+        else:
+            print(_("Successfully started Hexoshi. Quitting now as -q was passed."))
+    finally:
+        write_to_disk()
+
+
+asyncio.run(main())
diff -ruN a/hlib/game.py b/hlib/game.py
--- a/hlib/game.py
+++ b/hlib/game.py
@@ -20,13 +20,8 @@
 
 
 def update_fullscreen():
-    if hlib.fullscreen:
-        sge.game.scale = hlib.fsscale or None
-        sge.game.fullscreen = True
-    else:
-        sge.game.fullscreen = False
-        sge.game.scale = hlib.scale
-        sge.game.scale = None
+    # Web port: the page has its own full-screen button.
+    pass
 
 
 def refresh_screen(time_passed, delta_mult):