diff --git a/dev/tests/example.lua b/dev/tests/example.lua
index e69de29b..6c9546a8 100644
--- a/dev/tests/example.lua
+++ b/dev/tests/example.lua
@@ -0,0 +1,2 @@
+test.new_world("demo", "2019", "core:default")
+print(world.get_generator())
diff --git a/res/scripts/stdlib.lua b/res/scripts/stdlib.lua
index 9a5aa08a..d8a593b0 100644
--- a/res/scripts/stdlib.lua
+++ b/res/scripts/stdlib.lua
@@ -12,6 +12,7 @@ end
 if test then
     test.sleep = sleep
     test.name = __VC_TEST_NAME
+    test.new_world = core.new_world
 end
 
 ------------------------------------------------
diff --git a/src/Mainloop.cpp b/src/Mainloop.cpp
index 180e75f5..102aa7cd 100644
--- a/src/Mainloop.cpp
+++ b/src/Mainloop.cpp
@@ -3,7 +3,9 @@
 #include "debug/Logger.hpp"
 #include "engine.hpp"
 #include "frontend/screens/MenuScreen.hpp"
+#include "frontend/screens/LevelScreen.hpp"
 #include "window/Window.hpp"
+#include "world/Level.hpp"
 
 static debug::Logger logger("mainloop");
 
@@ -13,6 +15,10 @@ Mainloop::Mainloop(Engine& engine) : engine(engine) {
 void Mainloop::run() {
     auto& time = engine.getTime();
 
+    engine.setLevelConsumer([this](auto level) {
+        engine.setScreen(std::make_shared<LevelScreen>(&engine, std::move(level)));
+    });
+
     logger.info() << "starting menu screen";
     engine.setScreen(std::make_shared<MenuScreen>(&engine));
     
diff --git a/src/TestMainloop.cpp b/src/TestMainloop.cpp
index 617a65cd..955f4b26 100644
--- a/src/TestMainloop.cpp
+++ b/src/TestMainloop.cpp
@@ -1,8 +1,10 @@
 #include "TestMainloop.hpp"
 
 #include "logic/scripting/scripting.hpp"
+#include "logic/LevelController.hpp"
 #include "interfaces/Process.hpp"
 #include "debug/Logger.hpp"
+#include "world/Level.hpp"
 #include "engine.hpp"
 
 static debug::Logger logger("mainloop");
@@ -12,6 +14,8 @@ inline constexpr int TPS = 20;
 TestMainloop::TestMainloop(Engine& engine) : engine(engine) {
 }
 
+TestMainloop::~TestMainloop() = default;
+
 void TestMainloop::run() {
     const auto& coreParams = engine.getCoreParameters();
     auto& time = engine.getTime();
@@ -20,6 +24,9 @@ void TestMainloop::run() {
         logger.info() << "nothing to do";
         return;
     }
+    engine.setLevelConsumer([this](auto level) {
+        setLevel(std::move(level));
+    });
 
     logger.info() << "starting test " << coreParams.testFile;
     auto process = scripting::start_coroutine(coreParams.testFile);
@@ -29,3 +36,7 @@ void TestMainloop::run() {
     }
     logger.info() << "test finished";
 }
+
+void TestMainloop::setLevel(std::unique_ptr<Level> level) {
+    this->controller = std::make_unique<LevelController>(&engine, std::move(level));
+}
diff --git a/src/TestMainloop.hpp b/src/TestMainloop.hpp
index b0acc9a7..06ffae25 100644
--- a/src/TestMainloop.hpp
+++ b/src/TestMainloop.hpp
@@ -1,11 +1,19 @@
 #pragma once
 
+#include <memory>
+
+class Level;
+class LevelController;
 class Engine;
 
 class TestMainloop {
     Engine& engine;
+    std::unique_ptr<LevelController> controller;
 public:
     TestMainloop(Engine& engine);
+    ~TestMainloop();
 
     void run();
+
+    void setLevel(std::unique_ptr<Level> level);
 };
diff --git a/src/engine.cpp b/src/engine.cpp
index 622a2fdb..072bd5f6 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -19,6 +19,7 @@
 #include "frontend/menu.hpp"
 #include "frontend/screens/Screen.hpp"
 #include "frontend/screens/MenuScreen.hpp"
+#include "frontend/screens/LevelScreen.hpp"
 #include "graphics/render/ModelsGenerator.hpp"
 #include "graphics/core/DrawContext.hpp"
 #include "graphics/core/ImageData.hpp"
@@ -35,6 +36,7 @@
 #include "window/Events.hpp"
 #include "window/input.hpp"
 #include "window/Window.hpp"
+#include "world/Level.hpp"
 #include "Mainloop.hpp"
 #include "TestMainloop.hpp"
 
@@ -120,7 +122,7 @@ Engine::Engine(CoreParameters coreParameters)
     }
     keepAlive(settings.ui.language.observe([=](auto lang) {
         setLanguage(lang);
-    }, !langNotSet));
+    }, true));
     
     scripting::initialize(this);
     basePacks = files::read_list(resdir/fs::path("config/builtins.list"));
@@ -272,6 +274,10 @@ PacksManager Engine::createPacksManager(const fs::path& worldFolder) {
     return manager;
 }
 
+void Engine::setLevelConsumer(consumer<std::unique_ptr<Level>> levelConsumer) {
+    this->levelConsumer = std::move(levelConsumer);
+}
+
 void Engine::loadAssets() {
     logger.info() << "loading assets";
     Shader::preprocessor->setPaths(resPaths.get());
@@ -380,8 +386,10 @@ void Engine::loadContent() {
     ContentLoader::loadScripts(*content);
 
     langs::setup(resdir, langs::current->getId(), contentPacks);
-    loadAssets();
-    onAssetsLoaded();
+    if (!isHeadless()) {
+        loadAssets();
+        onAssetsLoaded();
+    }
 }
 
 void Engine::resetContent() {
@@ -445,6 +453,10 @@ void Engine::setLanguage(std::string locale) {
     }
 }
 
+void Engine::onWorldOpen(std::unique_ptr<Level> level) {
+    levelConsumer(std::move(level));
+}
+
 gui::GUI* Engine::getGUI() {
     return gui.get();
 }
diff --git a/src/engine.hpp b/src/engine.hpp
index fee92e81..55104cb1 100644
--- a/src/engine.hpp
+++ b/src/engine.hpp
@@ -21,6 +21,7 @@
 #include <vector>
 #include <mutex>
 
+class Level;
 class Screen;
 class EnginePaths;
 class ResPaths;
@@ -71,6 +72,7 @@ class Engine : public util::ObjectsKeeper {
     std::vector<std::string> basePacks;
     std::unique_ptr<gui::GUI> gui;
     Time time;
+    consumer<std::unique_ptr<Level>> levelConsumer;
     
     void loadControls();
     void loadSettings();
@@ -132,6 +134,8 @@ public:
     /// @brief Get engine resource paths controller
     ResPaths* getResPaths();
 
+    void onWorldOpen(std::unique_ptr<Level> level);
+
     /// @brief Get current Content instance
     const Content* getContent() const;
 
@@ -155,6 +159,8 @@ public:
 
     PacksManager createPacksManager(const fs::path& worldFolder);
 
+    void setLevelConsumer(consumer<std::unique_ptr<Level>> levelConsumer);
+
     SettingsHandler& getSettingsHandler();
 
     network::Network& getNetwork();
diff --git a/src/logic/EngineController.cpp b/src/logic/EngineController.cpp
index edd6efb7..27e254f3 100644
--- a/src/logic/EngineController.cpp
+++ b/src/logic/EngineController.cpp
@@ -150,9 +150,7 @@ static void load_world(Engine* engine, const std::shared_ptr<WorldFiles>& worldF
         auto& settings = engine->getSettings();
 
         auto level = World::load(worldFiles, settings, content, packs);
-        engine->setScreen(
-            std::make_shared<LevelScreen>(engine, std::move(level))
-        );
+        engine->onWorldOpen(std::move(level));
     } catch (const world_load_error& error) {
         guiutil::alert(
             engine->getGUI(),
@@ -229,7 +227,10 @@ void EngineController::createWorld(
     EnginePaths* paths = engine->getPaths();
     auto folder = paths->getWorldsFolder() / fs::u8path(name);
 
-    if (!menus::call(engine, [this, paths, folder]() {
+    if (engine->isHeadless()) {
+        engine->loadContent();
+        paths->setCurrentWorldFolder(folder);
+    } else if (!menus::call(engine, [this, paths, folder]() {
             engine->loadContent();
             paths->setCurrentWorldFolder(folder);
         })) {
@@ -244,7 +245,7 @@ void EngineController::createWorld(
         engine->getContent(),
         engine->getContentPacks()
     );
-    engine->setScreen(std::make_shared<LevelScreen>(engine, std::move(level)));
+    engine->onWorldOpen(std::move(level));
 }
 
 void EngineController::reopenWorld(World* world) {
diff --git a/src/world/World.cpp b/src/world/World.cpp
index 4eb2631a..cde3b3ce 100644
--- a/src/world/World.cpp
+++ b/src/world/World.cpp
@@ -95,6 +95,8 @@ std::unique_ptr<Level> World::create(
         content,
         packs
     );
+    logger.info() << "created world '" << name << "' (" << directory.u8string() << ")";
+    logger.info() << "world seed: " << seed << " generator: " << generator;
     auto level = std::make_unique<Level>(std::move(world), content, settings);
     level->players->create();
     return level;