diff --git a/MainWindow.gd b/MainWindow.gd
index 1d98926..b9ed7b7 100644
--- a/MainWindow.gd
+++ b/MainWindow.gd
@@ -41,7 +41,7 @@ var popup_backdrop: PopupBackdrop
 func _ready() -> void:
 	popup_backdrop = PopupBackdrop.add_to(self, _popups())
 	if OS.has_feature("macos"):
-		print("is_mac")
+		GameLog.debug("is_mac")
 	top_bar.search_pressed.connect(show_search)
 	top_bar.sync_pressed.connect(sync_soundtracks)
 	top_bar.statistics_pressed.connect(get_statistics)
@@ -60,7 +60,7 @@ func _ready() -> void:
 func _input(event: InputEvent) -> void:
 	if event is InputEventKey and event.pressed:
 		if event.alt_pressed && event.keycode == KEY_ENTER:
-			print("Alt + Enter pressed")
+			GameLog.debug("Alt + Enter pressed")
 			Settings.fullscreen = !Settings.fullscreen
 			if Settings.fullscreen == true:
 				DisplayServer.window_set_mode(DisplayServer.WINDOW_MODE_FULLSCREEN)
@@ -77,44 +77,44 @@ func _popups() -> Array[PopupWindow]:
 
 
 func show_search() -> void:
-	print("show_search")
+	GameLog.debug("show_search")
 	search_view.toggle()
 
 
 func show_about() -> void:
-	print("show_about")
+	GameLog.debug("show_about")
 	about_window.open()
 
 
 func show_shortcuts() -> void:
-	print("show_shortcuts")
+	GameLog.debug("show_shortcuts")
 	shortcuts_window.open()
 
 
 func show_qr() -> void:
-	print("show_qr")
+	GameLog.debug("show_qr")
 	qr_window.open()
 
 
 func get_statistics() -> void:
-	print("get_statistics")
+	GameLog.debug("get_statistics")
 	statistic_popup.visible = true
 	statistic_label.text = "Total amount of soundtracks in the playlist: " \
 			+ str(search_view.soundtracks.size())
 
 
 func sync_soundtracks() -> void:
-	print("sync_soundtracks")
+	GameLog.debug("sync_soundtracks")
 	sync_window.start_sync()
 
 
 func _on_sync_started() -> void:
-	print("_on_sync_started")
+	GameLog.debug("_on_sync_started")
 	top_bar.sync_button.disabled = false
 	quiz.lock_for_sync()
 
 
 func _on_sync_finished() -> void:
-	print("_on_sync_finished")
+	GameLog.debug("_on_sync_finished")
 	search_view.get_list_of_soundtracks()
 	quiz.on_sync_finished()
diff --git a/MusicPlayer.gd b/MusicPlayer.gd
index 74de4fd..29cd549 100644
--- a/MusicPlayer.gd
+++ b/MusicPlayer.gd
@@ -91,7 +91,7 @@ func play_or_pause() -> void:
 		audio_player.stream_paused = false
 		song_finished = false
 		audio_player.seek(playback_position)
-		print("continue")
+		GameLog.debug("continue")
 		progress_slider.max_value = round(stream.get_length())
 		if Settings.hide_ticks:
 			progress_slider.tick_count = 0
@@ -184,7 +184,7 @@ func play_song(song: AudioStream) -> void:
 	music_time_label.text = format_text(progress_slider.value, stream.get_length())
 
 func play_song_object(song_object_no: int) -> void:
-	print("play_song_object")
+	GameLog.debug("play_song_object")
 	if audio_player.is_playing():
 		audio_player.stop()
 		await get_tree().create_timer(0.5).timeout
@@ -204,7 +204,7 @@ func play_song_object(song_object_no: int) -> void:
 	Playlist.set_currently_playing_song(song_object_no)
 	Playlist.unset_is_playing()
 	if !Settings.hide_next_track:
-		print("Show answer now!!")
+		GameLog.debug("Show answer now!!")
 		Playlist.song_is_answered(song_object_no)
 	Playlist.song_has_played(song_object_no)
 	Playlist.song_is_playing(song_object_no)
@@ -229,8 +229,8 @@ func load_mp3(_path: String) -> AudioStream:
 func play_local_song() -> void:
 	if songs:
 		local_path = songs[0]
-		print(local_path)
-		print(FileAccess.file_exists(local_path))
+		GameLog.debug(local_path)
+		GameLog.debug(FileAccess.file_exists(local_path))
 		play_sound(load_mp3(local_path))
 
 func sound_test_local() -> void:
diff --git a/Player.gd b/Player.gd
index a5ad97f..83cb1ac 100644
--- a/Player.gd
+++ b/Player.gd
@@ -61,7 +61,7 @@ func change_character() -> void:
 	change_character_clicked.emit()
 
 func new_character_selected(character_texture: ImageTexture) -> void:
-	print("Back in player list with new")
+	GameLog.debug("Back in player list with new")
 	player_object.character = character_texture
 	set_player_character()
 
diff --git a/QRWindow.gd b/QRWindow.gd
index d13392a..336b1e8 100644
--- a/QRWindow.gd
+++ b/QRWindow.gd
@@ -19,7 +19,7 @@ func _ready() -> void:
 	var url: String = Settings.default_path + "/search"
 	qr_code_rect.data = url
 	url_label.text = qr_code_rect.data
-	print("QR code generated for: ", url)
+	GameLog.debug("QR code generated for: ", url)
 
 func open() -> void:
 	super()
diff --git a/SearchWindow.gd b/SearchWindow.gd
index d29d3ed..f56fc72 100644
--- a/SearchWindow.gd
+++ b/SearchWindow.gd
@@ -39,7 +39,7 @@ func close() -> void:
 	super()
 
 func search() -> void:
-	print(search_bar.text)
+	GameLog.debug(search_bar.text)
 	var search_text: String = search_bar.text
 	
 	if search_text == "":
@@ -153,7 +153,7 @@ func check_if_soundtrack_exists(soundtrack: String) -> bool:
 	return soundtrack_exists
 
 func get_list_of_soundtracks() -> void:
-	print("get_list_of_soundtracks")
+	GameLog.debug("get_list_of_soundtracks")
 	var handle_soundtracks: Callable = func handle_soundtracks(array) -> void:
 		if typeof(array) == TYPE_ARRAY:
 			# Reuse existing labels: hide all and add to pool
@@ -164,7 +164,7 @@ func get_list_of_soundtracks() -> void:
 			for soundtrack: String in soundtracks:
 				add_soundtrack_reuse(soundtrack)
 		else:
-			print("Unexpected data")
+			GameLog.warning("Unexpected data")
 	MusicServerClient.fetch_all_soundtracks_ordered(handle_soundtracks)
 
 ## Replaces the searchable soundtracks and precomputes their search forms.
diff --git a/SettingsWindow.gd b/SettingsWindow.gd
index bc70a6e..e9f927b 100644
--- a/SettingsWindow.gd
+++ b/SettingsWindow.gd
@@ -203,22 +203,22 @@ func increase_hide_for_seconds() -> void:
 	hide_for_seconds_label.text = str(Settings.hide_for_seconds)
 
 func select_server(new_server: int) -> void:
-	print("select_server")
+	GameLog.debug("select_server")
 	Settings.default_path = select_server_button.get_item_text(new_server)
 	Settings.selected_server = new_server
-	print("Settings.default_path: " + Settings.default_path)
-	print("Settings.selected_server: " + str(Settings.selected_server))
-	print("new_server: " + str(new_server))
-	print("select_server_button.get_item_text(new_server): " + select_server_button.get_item_text(new_server))
+	GameLog.debug("Settings.default_path: " + Settings.default_path)
+	GameLog.debug("Settings.selected_server: " + str(Settings.selected_server))
+	GameLog.debug("new_server: " + str(new_server))
+	GameLog.debug("select_server_button.get_item_text(new_server): " + select_server_button.get_item_text(new_server))
 	server_changed.emit()
 
 func set_selected_server(new_server: int) -> void:
-	print("set_selected_server")
+	GameLog.debug("set_selected_server")
 	select_server_button.select(new_server)
 	Settings.default_path = select_server_button.get_item_text(new_server)
 	Settings.selected_server = new_server
-	print("Settings.default_path: " + Settings.default_path)
-	print("Settings.selected_server: " + str(Settings.selected_server))
-	print("new_server: " + str(new_server))
-	print("select_server_button.get_item_text(new_server): " + select_server_button.get_item_text(new_server))
+	GameLog.debug("Settings.default_path: " + Settings.default_path)
+	GameLog.debug("Settings.selected_server: " + str(Settings.selected_server))
+	GameLog.debug("new_server: " + str(new_server))
+	GameLog.debug("select_server_button.get_item_text(new_server): " + select_server_button.get_item_text(new_server))
 	server_changed.emit()
diff --git a/SongObject.gd b/SongObject.gd
index 48d9290..a390df3 100644
--- a/SongObject.gd
+++ b/SongObject.gd
@@ -42,12 +42,12 @@ func get_song_info() -> String:
 		return "??? - ???"
 
 func add_point(player_id: String) -> void:
-	print("add_point")
+	GameLog.debug("add_point")
 	if !players_given_point.has(player_id):
 		players_given_point.append(player_id)
 
 func remove_point(player_id: String) -> void:
-	print("remove_point")
+	GameLog.debug("remove_point")
 	players_given_point.erase(player_id)
 
 func _to_string() -> String:
diff --git a/character.gd b/character.gd
index 3de4ac0..3f19408 100644
--- a/character.gd
+++ b/character.gd
@@ -22,10 +22,11 @@ func set_character_name(character_name: String) -> void:
 		var img: Image = Image.new()
 		var err: Error = img.load_png_from_buffer(image)
 		if err != OK:
-			print(err)
+			GameLog.debug("Character image is not a PNG, trying JPG: ", error_string(err))
 			var err2: Error = img.load_jpg_from_buffer(image)
 			if err2 != OK:
-				print(err2)
+				GameLog.warning("Could not load the image for ", character_name, ": ",
+						error_string(err2))
 		var new_image: ImageTexture = ImageTexture.new()
 		new_image.set_image(img)
 		character_image.custom_minimum_size = Vector2(200, 100)
@@ -42,5 +43,5 @@ func _input(event: InputEvent) -> void:
 		if event is InputEventMouseButton && event.is_pressed() && event.get_button_index() == MOUSE_BUTTON_LEFT:
 			var evLocal: InputEvent = make_input_local(event)
 			if Rect2(Vector2(0, 0), panel.size).has_point(evLocal.position):
-				print(character_name_label.text)
+				GameLog.debug(character_name_label.text)
 				new_character_selected.emit(character_image.texture)
diff --git a/game_log.gd b/game_log.gd
new file mode 100644
index 0000000..6c79935
--- /dev/null
+++ b/game_log.gd
@@ -0,0 +1,21 @@
+extends Node
+## Writes messages about what the game is doing, for finding problems.
+##
+## Registered as the [code]GameLog[/code] autoload. Use [method debug] instead of
+## [code]print()[/code]: the messages show in debug builds and the editor, and are left
+## out of released games. Problems the player may notice go through [method warning].
+
+
+## Prints [param parts] joined together, like [code]print()[/code], in debug builds only.
+func debug(...parts: Array) -> void:
+	if OS.is_debug_build():
+		print(_join(parts))
+
+
+## Reports a problem in the editor's debugger and the console, in every build.
+func warning(...parts: Array) -> void:
+	push_warning(_join(parts))
+
+
+func _join(parts: Array) -> String:
+	return "".join(parts.map(func(part: Variant) -> String: return str(part)))
diff --git a/game_log.gd.uid b/game_log.gd.uid
new file mode 100644
index 0000000..9dde246
--- /dev/null
+++ b/game_log.gd.uid
@@ -0,0 +1 @@
+uid://c37mlo6svk03q
diff --git a/inspiration_list.gd b/inspiration_list.gd
index 5de3937..40a08ef 100644
--- a/inspiration_list.gd
+++ b/inspiration_list.gd
@@ -49,12 +49,12 @@ func _process(delta: float) -> void:
 
 ## Fetches every soundtrack from the server and shows them.
 func load_from_server() -> void:
-	print("load_from_server")
+	GameLog.debug("load_from_server")
 	var populate_list: Callable = func populate_list(array) -> void:
 		if typeof(array) == TYPE_ARRAY:
 			show_soundtracks(array)
 		else:
-			print("Unexpected data")
+			GameLog.warning("Unexpected data")
 	MusicServerClient.fetch_all_soundtracks(populate_list)
 
 
diff --git a/new_character_select.gd b/new_character_select.gd
index fd720b9..42bebbf 100644
--- a/new_character_select.gd
+++ b/new_character_select.gd
@@ -22,18 +22,18 @@ func _ready() -> void:
 	close_timer.timeout.connect(_on_close_timeout)
 
 func _on_close_timeout() -> void:
-	print("_on_close_timeout!")
+	GameLog.debug("_on_close_timeout!")
 	Settings.character_select_open = false
 	close_timer.stop()
 
 func load_characters() -> void:
-	print("load_characters")
+	GameLog.debug("load_characters")
 	var fetch_character_list: Callable = func fetch_character_list(list) -> void:
-		print("fetch_character_list")
+		GameLog.debug("fetch_character_list")
 		Settings.delete_children(character_grid)
 		if typeof(list) == TYPE_ARRAY:
 			for character_name: String in list:
-				print("character_name ", character_name)
+				GameLog.debug("character_name ", character_name)
 				var character_box: Character = character.instantiate()
 				character_grid.add_child(character_box)
 				character_box.custom_minimum_size = Vector2(235, 145)
@@ -43,7 +43,7 @@ func load_characters() -> void:
 	MusicServerClient.fetch_character_list(fetch_character_list)
 
 func show_grid(player_name: String) -> void:
-	print("show_grid")
+	GameLog.debug("show_grid")
 	title_label.text = "Select character for " + player_name
 	close_timer.stop()
 	open()
@@ -55,7 +55,7 @@ func close() -> void:
 	Settings.character_select_open = false
 
 func _on_character_selected(texture: ImageTexture) -> void:
-	print("_on_character_selected")
+	GameLog.debug("_on_character_selected")
 	# Not close(): character_select_open stays true until close_timer fires, so the click
 	# that picked the character does not also select a song behind it
 	self.visible = false
diff --git a/players_panel.gd b/players_panel.gd
index 363b50a..1b1f84c 100644
--- a/players_panel.gd
+++ b/players_panel.gd
@@ -41,7 +41,7 @@ func _ready() -> void:
 
 ## Shows or hides the row for adding players, and the buttons for removing them.
 func add_players() -> void:
-	print("add_players")
+	GameLog.debug("add_players")
 	Settings.edit_players = !Settings.edit_players
 	add_player_container.visible = !add_player_container.visible
 	new_player_name_field.grab_focus()
@@ -50,7 +50,7 @@ func add_players() -> void:
 ## Adds a player with the name in the name field, unless it is empty or there are
 ## already as many players as there can be.
 func add_player() -> void:
-	print("add_player")
+	GameLog.debug("add_player")
 	if new_player_name_field.text != "" && Settings.player_array.size() < Settings.MAX_NUMBER_OF_PLAYERS:
 		var new_player_object: PlayerObject = PlayerObject.new(new_player_name_field.text)
 		new_player_name_field.text = ""
@@ -62,11 +62,11 @@ func add_player() -> void:
 ## Shows the players in [code]Settings.player_array[/code] again, e.g. after their
 ## points were reset.
 func reload() -> void:
-	print("load_players")
+	GameLog.debug("load_players")
 	Settings.delete_children(players_list_container)
 	var counter: int = 0
 	for player_object: PlayerObject in Settings.player_array:
-		print(player_object.player_name)
+		GameLog.debug(player_object.player_name)
 
 		var new_player: Player = _player_row.instantiate()
 		new_player.player_object = player_object
@@ -84,7 +84,7 @@ func _on_change_character_clicked(row: Player, player_name: String) -> void:
 
 
 func _on_player_removed(player_object: PlayerObject) -> void:
-	print("_on_player_removed ", player_object.player_name)
+	GameLog.debug("_on_player_removed ", player_object.player_name)
 	Settings.player_array.erase(player_object)
 	reload()
 	player_removed.emit(player_object)
diff --git a/playlist.gd b/playlist.gd
index cebc19b..08dec57 100644
--- a/playlist.gd
+++ b/playlist.gd
@@ -35,10 +35,10 @@ func song_is_answered(song_no: int = currently_playing_song) -> void:
 	# Nothing is playing yet (-1); a negative index would answer the last, unplayed song
 	if song_no < 0 || song_no >= song_object_array.size():
 		return
-	print("show_answer_pressed song_object: ", song_object_array[song_no]._to_string())
+	GameLog.debug("show_answer_pressed song_object: ", song_object_array[song_no]._to_string())
 	song_object_array[song_no].is_answered = true
 	if Settings.add_to_stats:
-		print("add to stats: ", song_no)
+		GameLog.debug("add to stats: ", song_no)
 		MusicServerClient.mark_song_played(song_no)
 
 func add_to_playlist(new_song_object: SongObject) -> void:
diff --git a/project.godot b/project.godot
index 6929309..4e4c0ce 100644
--- a/project.godot
+++ b/project.godot
@@ -22,6 +22,7 @@ config/icon="res://icon.svg"
 
 [autoload]
 
+GameLog="*res://game_log.gd"
 Settings="*res://Settings.gd"
 Playlist="*res://playlist.gd"
 MusicServerClient="*res://music_server_client.gd"
diff --git a/quiz.gd b/quiz.gd
index 770625c..e12f0aa 100644
--- a/quiz.gd
+++ b/quiz.gd
@@ -69,7 +69,7 @@ var popup_backdrop: PopupBackdrop
 func _ready() -> void:
 	popup_backdrop = PopupBackdrop.add_to(self, _popups())
 	if OS.has_feature("debug"):
-		print("is_debug")
+		GameLog.debug("is_debug")
 		debug_label.visible = true
 		Settings.is_debug = true
 		settings_window.set_winning_score(5)
@@ -103,19 +103,19 @@ func _ready() -> void:
 func _input(event: InputEvent) -> void:
 	if event is InputEventKey and event.pressed:
 		if event.alt_pressed && event.keycode == KEY_UP:
-			print("Alt + UP pressed")
+			GameLog.debug("Alt + UP pressed")
 			music_player_container.change_volume(0.05)
 		if event.alt_pressed && event.keycode == KEY_DOWN:
-			print("Alt + DOWN pressed")
+			GameLog.debug("Alt + DOWN pressed")
 			music_player_container.change_volume(-0.05)
 		if event.alt_pressed && event.ctrl_pressed && event.keycode == KEY_LEFT:
-			print("Ctrl + Alt + LEFT pressed")
+			GameLog.debug("Ctrl + Alt + LEFT pressed")
 			music_player_container.restart()
 		elif event.alt_pressed && event.keycode == KEY_LEFT:
-			print("Alt + LEFT pressed")
+			GameLog.debug("Alt + LEFT pressed")
 			music_player_container.seek(-5)
 		if event.alt_pressed && event.keycode == KEY_RIGHT:
-			print("Alt + RIGHT pressed")
+			GameLog.debug("Alt + RIGHT pressed")
 			music_player_container.seek(5)
 
 
@@ -135,27 +135,27 @@ func on_sync_finished() -> void:
 
 ## Reloads the soundtracks, playlist and characters from the server.
 func refresh_from_server() -> void:
-	print("refresh_from_server")
+	GameLog.debug("refresh_from_server")
 	inspiration_list.load_from_server()
 	reset_playlist()
 	new_character_select.load_characters()
 
 
 func _on_server_changed() -> void:
-	print("_on_server_changed")
+	GameLog.debug("_on_server_changed")
 	refresh_from_server()
 	reset_points()
 	server_changed.emit()
 
 
 func show_answer_pressed() -> void:
-	print("show_answer_pressed")
+	GameLog.debug("show_answer_pressed")
 	Playlist.song_is_answered()
 	update_song_list()
 
 
 func play_next_song() -> void:
-	print("play_next_song ", Playlist.latest_played_song)
+	GameLog.debug("play_next_song ", Playlist.latest_played_song)
 	if Playlist.first_song_played:
 		Playlist.set_latest_played_song()
 	Playlist.first_song_played = true
@@ -183,7 +183,7 @@ func _on_song_added() -> void:
 
 
 func update_song_list() -> void:
-	print("update_song_list")
+	GameLog.debug("update_song_list")
 	if Playlist.currently_playing_song >= 0:
 		now_playing.show_song(Playlist.get_current_soundtrack_title(),
 				Playlist.get_current_song_title())
@@ -191,10 +191,10 @@ func update_song_list() -> void:
 
 
 func song_object_clicked(song_no: int) -> void:
-	print("Clicked Song Object: ", Playlist.song_object_array[song_no].to_string())
+	GameLog.debug("Clicked Song Object: ", Playlist.song_object_array[song_no].to_string())
 	if Settings.character_select_open == false:
 		if Playlist.get_song(song_no) == null:
-			print("has no song, need to download")
+			GameLog.debug("has no song, need to download")
 			var song_downloaded: Callable = func song_downloaded(body: PackedByteArray) -> void:
 				var sound: AudioStream = AudioStreamMP3.new()
 				sound.data = body
@@ -202,12 +202,12 @@ func song_object_clicked(song_no: int) -> void:
 				music_player_container.play_song_object(song_no)
 			MusicServerClient.fetch_song(song_no, song_downloaded)
 		else:
-			print("song already downloaded")
+			GameLog.debug("song already downloaded")
 			music_player_container.play_song_object(song_no)
 
 
 func reset_playlist() -> void:
-	print("reset_playlist")
+	GameLog.debug("reset_playlist")
 	var playlist_reset_done: Callable = func playlist_reset_done() -> void:
 		Playlist.reset_playlist()
 		song_loader.load_song_list()
@@ -216,7 +216,7 @@ func reset_playlist() -> void:
 
 
 func reset_points() -> void:
-	print("reset_points")
+	GameLog.debug("reset_points")
 	for player_objects: PlayerObject in Settings.player_array:
 		player_objects.reset_points()
 	players_panel.reload()
@@ -227,7 +227,7 @@ func reset_points() -> void:
 
 
 func show_settings() -> void:
-	print("show_settings")
+	GameLog.debug("show_settings")
 	settings_window.open()
 
 
@@ -242,7 +242,7 @@ func _on_player_added(new_player_object: PlayerObject) -> void:
 
 
 func _on_point_given(player_object: PlayerObject) -> void:
-	print("_on_point_given")
+	GameLog.debug("_on_point_given")
 	event_logged.emit(player_object.player_name + " got a point")
 	if Playlist.currently_playing_song >= 0:
 		Playlist.add_point(player_object.id)
@@ -254,7 +254,7 @@ func _on_make_point_given_sound() -> void:
 
 
 func _on_point_taken(player_object: PlayerObject) -> void:
-	print("_on_point_taken")
+	GameLog.debug("_on_point_taken")
 	event_logged.emit(player_object.player_name + " lost a point")
 	music_player_container.play_sound_effect(preload("res://sounds/itemequip.wav"))
 	if Playlist.currently_playing_song >= 0:
@@ -263,7 +263,7 @@ func _on_point_taken(player_object: PlayerObject) -> void:
 
 
 func _on_player_won(player_object: PlayerObject) -> void:
-	print("_on_player_won")
+	GameLog.debug("_on_player_won")
 	winner_window.show_winner(player_object)
 	music_player_container.play_song(preload("res://sounds/winning.mp3"))
 	# Songs played after the game is won don't count towards the statistics
@@ -278,14 +278,14 @@ func _on_player_removed(player_object: PlayerObject) -> void:
 
 
 func _on_player_change_character_clicked(new_player: Player, player_name: String) -> void:
-	print("_on_player_change_character_clicked")
+	GameLog.debug("_on_player_change_character_clicked")
 	current_player = new_player
-	print("Change character for: " + player_name)
+	GameLog.debug("Change character for: " + player_name)
 	new_character_select.show_grid(player_name)
 
 
 func _on_new_character_selected(character_texture: ImageTexture) -> void:
-	print("_on_new_character_selected")
+	GameLog.debug("_on_new_character_selected")
 	current_player.new_character_selected(character_texture)
 
 
@@ -298,7 +298,7 @@ func open() -> void:
 
 
 func _on_file_dialog_dir_selected(path: String) -> void:
-	print(path)
+	GameLog.debug(path)
 	dir_contents(path)
 
 
@@ -311,13 +311,13 @@ func dir_contents(path: String) -> void:
 		var soundtracks: Array = []
 		while file_name != "":
 			if dir.current_is_dir():
-				#print("Found directory: " + file_name)
+				#GameLog.debug("Found directory: " + file_name)
 				soundtracks.append(file_name)
 			else:
-				#print("Found file: " + file_name)
+				#GameLog.debug("Found file: " + file_name)
 				if file_name.ends_with(".mp3"):
 					songs.append(path + "/" + file_name)
 			file_name = dir.get_next()
 		inspiration_list.show_soundtracks(soundtracks)
 	else:
-		print("An error occurred when trying to access the path.")
+		GameLog.warning("An error occurred when trying to access the path.")
diff --git a/song_loader.gd b/song_loader.gd
index 613347e..6fba366 100644
--- a/song_loader.gd
+++ b/song_loader.gd
@@ -20,7 +20,7 @@ var retry_seconds: float = 5.0
 ## Loads the songs already in the server playlist, then starts preloading new ones.
 ## Preloading waits for the list, because loading the list clears the playlist.
 func load_song_list() -> void:
-	print("load_song_list")
+	GameLog.debug("load_song_list")
 	var song_list_fetched: Callable = func song_list_fetched(data) -> void:
 		Playlist.clear_song_list()
 		if typeof(data) == TYPE_ARRAY:
@@ -33,7 +33,7 @@ func load_song_list() -> void:
 				new_song_object.has_played = true
 				Playlist.add_to_playlist(new_song_object)
 		elif data != null:
-			print("Unexpected data")
+			GameLog.warning("Unexpected data")
 		Playlist.update_last_played_song()
 		song_list_loaded.emit()
 		fetch_song_if_idle()
@@ -42,7 +42,7 @@ func load_song_list() -> void:
 
 ## Starts downloading one more song, which keeps downloading until the cache is full.
 func fetch_song() -> void:
-	print("fetch_song")
+	GameLog.debug("fetch_song")
 	Playlist.is_song_downloading = true
 	_download_random_song(SongObject.new())
 
@@ -64,7 +64,7 @@ func fill_cache() -> void:
 # the server and the game keep the same songs in their playlists.
 func _download_random_song(new_song_object: SongObject) -> void:
 	var song_downloaded: Callable = func song_downloaded(body: PackedByteArray) -> void:
-		print("song_downloaded")
+		GameLog.debug("song_downloaded")
 		var sound: AudioStream = AudioStreamMP3.new()
 		sound.data = body
 		new_song_object.song = sound
@@ -80,11 +80,11 @@ func _add_song_to_queue(new_song_object: SongObject) -> void:
 
 func _fetch_song_info(new_song_object: SongObject) -> void:
 	var song_info_fetched: Callable = func song_info_fetched(data_received: Dictionary) -> void:
-		print("song_info_fetched")
+		GameLog.debug("song_info_fetched")
 		new_song_object.song_number = data_received.SongNo
 		new_song_object.soundtrack_title = data_received.Soundtrack
 		new_song_object.song_title = data_received.Song
-		print("new_song_object: ", new_song_object.to_string())
+		GameLog.debug("new_song_object: ", new_song_object.to_string())
 		Playlist.add_to_playlist(new_song_object)
 		if Playlist.should_preload_more_songs():
 			fetch_song()
@@ -96,5 +96,5 @@ func _fetch_song_info(new_song_object: SongObject) -> void:
 
 
 func _retry_later(step: Callable) -> void:
-	print("Song download failed, retrying in %s seconds" % retry_seconds)
+	GameLog.warning("Song download failed, retrying in %s seconds" % retry_seconds)
 	get_tree().create_timer(retry_seconds).timeout.connect(step)
diff --git a/sync_window.gd b/sync_window.gd
index 34869cb..652890a 100644
--- a/sync_window.gd
+++ b/sync_window.gd
@@ -83,7 +83,7 @@ func show_section_if_has_data(data: Variant, vbox: VBoxContainer, separator: VSe
 		return false
 
 func start_sync() -> void:
-	print("start_sync")
+	GameLog.debug("start_sync")
 	self.visible = true
 	if has_synced:
 		# Already synced, just show the results
@@ -98,10 +98,10 @@ func start_sync() -> void:
 		MusicServerClient.start_sync(sync_request_sent)
 
 func _on_sync_timeout() -> void:
-	print("_on_sync_timeout!")
+	GameLog.debug("_on_sync_timeout!")
 	var get_progress: Callable = func get_progress(data_received: Dictionary) -> void:
-		print("get_progress")
-		print("data_received: ", data_received)
+		GameLog.debug("get_progress")
+		GameLog.debug("data_received: ", data_received)
 		if data_received != null:
 			if data_received.has("progress"):
 				sync_progress_bar.value = int(data_received.progress)
@@ -176,7 +176,7 @@ func on_sync_finished(data_received: Dictionary) -> void:
 	sync_time.text = "Total time: " + data_received.total_time if data_received.has("total_time") else ""
 	Settings.currently_syncing = false
 	sync_timer.stop()
-	print("sync finished")
+	GameLog.debug("sync finished")
 	show_sync_result()
 	restart_sync_button.visible = true
 	sync_finished.emit()
diff --git a/tests/unit/test_game_log.gd b/tests/unit/test_game_log.gd
new file mode 100644
index 0000000..975b874
--- /dev/null
+++ b/tests/unit/test_game_log.gd
@@ -0,0 +1,23 @@
+extends GdUnitTestSuite
+## GameLog joins its arguments like print() does.
+
+
+func test_joins_parts_without_spaces_like_print() -> void:
+	assert_str(GameLog._join(["Song ", 3, " of ", 10.5])).is_equal("Song 3 of 10.5")
+
+
+func test_joins_any_kind_of_value() -> void:
+	assert_str(GameLog._join([null, true, [1, 2], {"a": 1}])) \
+			.is_equal("<null>true[1, 2]{ \"a\": 1 }")
+
+
+func test_no_parts_gives_an_empty_line() -> void:
+	assert_str(GameLog._join([])).is_empty()
+
+
+func test_debug_takes_any_number_of_arguments() -> void:
+	GameLog.debug()
+	GameLog.debug("one")
+	GameLog.debug("one", 2, Vector2.ONE)
+	# Reaching this line means none of the calls failed
+	assert_bool(true).is_true()
diff --git a/tests/unit/test_game_log.gd.uid b/tests/unit/test_game_log.gd.uid
new file mode 100644
index 0000000..335c06d
--- /dev/null
+++ b/tests/unit/test_game_log.gd.uid
@@ -0,0 +1 @@
+uid://delnqk8yt0hes