diff --git a/src/Main.cpp b/src/Main.cpp
index 5f5d179..87f1d87 100644
--- a/src/Main.cpp
+++ b/src/Main.cpp
@@ -8,7 +8,7 @@ void alai::Main::_register_methods()
     godot::register_method("_physics_process", &Main::_physics_process);
     godot::register_method("_on_monitor_loaded", &Main::_on_monitor_loaded);
     godot::register_property<Main, godot::String>("game_version", &Main::set_game_version, &Main::get_game_version, godot::String(alai::game_version.c_str()));
-    godot::register_property<Main, godot::Ref<godot::PackedScene>>("level", &Main::set_level, &Main::get_level, NULL, GODOT_METHOD_RPC_MODE_DISABLED, GODOT_PROPERTY_USAGE_DEFAULT, GODOT_PROPERTY_HINT_RESOURCE_TYPE, godot::String("PackedScene"));
+    godot::register_property<Main, godot::Ref<godot::PackedScene>>("level", &Main::set_level, &Main::get_level, nullptr, GODOT_METHOD_RPC_MODE_DISABLED, GODOT_PROPERTY_USAGE_DEFAULT, GODOT_PROPERTY_HINT_RESOURCE_TYPE, godot::String("PackedScene"));
     godot::register_property<Main, bool>("full_screen", &Main::set_full_screen, &Main::get_full_screen, alai::full_screen);
     godot::register_property<Main, godot::Vector2>("window_size", &Main::set_window_size, &Main::get_window_size, alai::window_size);
     godot::register_property<Main, int8_t>("launch_screen", &Main::set_launch_screen, &Main::get_launch_screen, alai::launch_screen);