diff --git a/headers/enduro2d/core/engine.hpp b/headers/enduro2d/core/engine.hpp
index dcc070db..df50e01c 100644
--- a/headers/enduro2d/core/engine.hpp
+++ b/headers/enduro2d/core/engine.hpp
@@ -62,7 +62,7 @@ namespace e2d
 
     class engine::debug_parameters {
     public:
-        debug_parameters& log_filename(str_view value);
+        debug_parameters& log_filename(str value) noexcept;
         debug_parameters& file_logging(bool value) noexcept;
         debug_parameters& console_logging(bool value) noexcept;
 
@@ -81,7 +81,7 @@ namespace e2d
 
     class engine::window_parameters {
     public:
-        window_parameters& caption(str_view value);
+        window_parameters& caption(str value) noexcept;
         window_parameters& size(const v2u& value) noexcept;
         window_parameters& vsync(bool value) noexcept;
         window_parameters& resizable(bool value) noexcept;
@@ -123,16 +123,16 @@ namespace e2d
     class engine::parameters {
     public:
         parameters() = delete;
-        parameters(str_view game_name, str_view company_name);
+        parameters(str game_name, str company_name) noexcept;
 
-        parameters& game_name(str_view value);
-        parameters& company_name(str_view value);
+        parameters& game_name(str value) noexcept;
+        parameters& company_name(str value) noexcept;
         parameters& without_audio(bool value);
         parameters& without_network(bool value);
         parameters& without_graphics(bool value);
-        parameters& debug_params(const debug_parameters& value);
-        parameters& window_params(const window_parameters& value);
-        parameters& timer_params(const timer_parameters& value);
+        parameters& debug_params(debug_parameters value) noexcept;
+        parameters& window_params(window_parameters value) noexcept;
+        parameters& timer_params(timer_parameters value) noexcept;
 
         str& game_name() noexcept;
         str& company_name() noexcept;
@@ -145,9 +145,9 @@ namespace e2d
 
         const str& game_name() const noexcept;
         const str& company_name() const noexcept;
-        const bool& without_audio() const noexcept;
-        const bool& without_network() const noexcept;
-        const bool& without_graphics() const noexcept;
+        bool without_audio() const noexcept;
+        bool without_network() const noexcept;
+        bool without_graphics() const noexcept;
         const debug_parameters& debug_params() const noexcept;
         const window_parameters& window_params() const noexcept;
         const timer_parameters& timer_params() const noexcept;
diff --git a/headers/enduro2d/high/library.hpp b/headers/enduro2d/high/library.hpp
index 03ed4235..4755cfd9 100644
--- a/headers/enduro2d/high/library.hpp
+++ b/headers/enduro2d/high/library.hpp
@@ -66,7 +66,7 @@ namespace e2d
 
     class library final : public module<library> {
     public:
-        library(const url& root, deferrer& deferrer);
+        library(url root);
         ~library() noexcept final;
 
         const url& root() const noexcept;
@@ -101,7 +101,6 @@ namespace e2d
         void wait_all_loading_assets_() noexcept;
     private:
         url root_;
-        deferrer& deferrer_;
         std::atomic<bool> cancelled_{false};
     private:
         mutable asset_cache cache_;
diff --git a/headers/enduro2d/high/library.inl b/headers/enduro2d/high/library.inl
index ea57b966..8359bc7b 100644
--- a/headers/enduro2d/high/library.inl
+++ b/headers/enduro2d/high/library.inl
@@ -44,9 +44,8 @@ namespace e2d
     // library
     //
 
-    inline library::library(const url& root, deferrer& deferrer)
-    : root_(root)
-    , deferrer_(deferrer) {}
+    inline library::library(url root)
+    : root_(std::move(root)) {}
 
     inline library::~library() noexcept {
         cancelled_.store(true);
@@ -73,7 +72,7 @@ namespace e2d
     template < typename Asset >
     typename Asset::load_result library::load_main_asset(str_view address) const {
         auto p = load_main_asset_async<Asset>(address);
-        deferrer_.active_safe_wait_promise(p);
+        the<deferrer>().active_safe_wait_promise(p);
         return p.get_or_default(nullptr);
     }
 
@@ -146,7 +145,7 @@ namespace e2d
     template < typename Asset, typename Nested >
     typename Nested::load_result library::load_asset(str_view address) const {
         auto p = load_asset_async<Asset, Nested>(address);
-        deferrer_.active_safe_wait_promise(p);
+        the<deferrer>().active_safe_wait_promise(p);
         return p.get_or_default(nullptr);
     }
 
@@ -210,7 +209,7 @@ namespace e2d
             }
             const auto loading_asset_copy = loading_assets_.back();
             lock.unlock();
-            loading_asset_copy->wait(deferrer_);
+            loading_asset_copy->wait(the<deferrer>());
         }
     }
 
diff --git a/headers/enduro2d/high/starter.hpp b/headers/enduro2d/high/starter.hpp
index e313a000..22c92f69 100644
--- a/headers/enduro2d/high/starter.hpp
+++ b/headers/enduro2d/high/starter.hpp
@@ -19,6 +19,7 @@ namespace e2d
         class application;
         using application_uptr = std::unique_ptr<application>;
     public:
+        class library_parameters;
         class parameters;
     public:
         starter(int argc, char *argv[], const parameters& params);
@@ -41,6 +42,19 @@ namespace e2d
         virtual bool on_should_close();
     };
 
+    //
+    // starter::library_parameters
+    //
+
+    class starter::library_parameters {
+    public:
+        library_parameters& root(url value) noexcept;
+        url& root() noexcept;
+        const url& root() const noexcept;
+    private:
+        url root_{"resources://bin/library"};
+    };
+
     //
     // starter::parameters
     //
@@ -48,19 +62,19 @@ namespace e2d
     class starter::parameters {
     public:
         parameters() = delete;
-        parameters(const engine::parameters& engine_params);
+        parameters(engine::parameters engine_params) noexcept;
 
-        parameters& library_root(const url& value);
-        parameters& engine_params(const engine::parameters& value);
+        parameters& engine_params(engine::parameters value) noexcept;
+        parameters& library_params(library_parameters value) noexcept;
 
-        url& library_root() noexcept;
         engine::parameters& engine_params() noexcept;
+        library_parameters& library_params() noexcept;
 
-        const url& library_root() const noexcept;
         const engine::parameters& engine_params() const noexcept;
+        const library_parameters& library_params() const noexcept;
     private:
-        url library_root_{"resources://bin/library"};
         engine::parameters engine_params_;
+        library_parameters library_params_;
     };
 }
 
diff --git a/sources/enduro2d/core/engine.cpp b/sources/enduro2d/core/engine.cpp
index 9efef894..3b9833fc 100644
--- a/sources/enduro2d/core/engine.cpp
+++ b/sources/enduro2d/core/engine.cpp
@@ -67,8 +67,8 @@ namespace e2d
     // engine::debug_parameters
     //
 
-    engine::debug_parameters& engine::debug_parameters::log_filename(str_view value) {
-        log_filename_ = value;
+    engine::debug_parameters& engine::debug_parameters::log_filename(str value) noexcept {
+        log_filename_ = std::move(value);
         return *this;
     }
 
@@ -120,8 +120,8 @@ namespace e2d
     // engine::window_parameters
     //
 
-    engine::window_parameters& engine::window_parameters::caption(str_view value) {
-        caption_ = value;
+    engine::window_parameters& engine::window_parameters::caption(str value) noexcept {
+        caption_ = std::move(value);
         return *this;
     }
 
@@ -169,17 +169,17 @@ namespace e2d
     // engine::parameters
     //
 
-    engine::parameters::parameters(str_view game_name, str_view company_name)
-    : game_name_(game_name)
-    , company_name_(company_name) {}
+    engine::parameters::parameters(str game_name, str company_name) noexcept
+    : game_name_(std::move(game_name))
+    , company_name_(std::move(company_name)) {}
 
-    engine::parameters& engine::parameters::game_name(str_view value) {
-        game_name_ = value;
+    engine::parameters& engine::parameters::game_name(str value) noexcept {
+        game_name_ = std::move(value);
         return *this;
     }
 
-    engine::parameters& engine::parameters::company_name(str_view value) {
-        company_name_ = value;
+    engine::parameters& engine::parameters::company_name(str value) noexcept {
+        company_name_ = std::move(value);
         return *this;
     }
 
@@ -198,18 +198,18 @@ namespace e2d
         return *this;
     }
 
-    engine::parameters& engine::parameters::debug_params(const debug_parameters& value) {
-        debug_params_ = value;
+    engine::parameters& engine::parameters::debug_params(debug_parameters value) noexcept {
+        debug_params_ = std::move(value);
         return *this;
     }
 
-    engine::parameters& engine::parameters::window_params(const window_parameters& value) {
-        window_params_ = value;
+    engine::parameters& engine::parameters::window_params(window_parameters value) noexcept {
+        window_params_ = std::move(value);
         return *this;
     }
 
-    engine::parameters& engine::parameters::timer_params(const timer_parameters& value) {
-        timer_params_ = value;
+    engine::parameters& engine::parameters::timer_params(timer_parameters value) noexcept {
+        timer_params_ = std::move(value);
         return *this;
     }
 
@@ -253,15 +253,15 @@ namespace e2d
         return company_name_;
     }
 
-    const bool& engine::parameters::without_audio() const noexcept {
+    bool engine::parameters::without_audio() const noexcept {
         return without_audio_;
     }
 
-    const bool& engine::parameters::without_network() const noexcept {
+    bool engine::parameters::without_network() const noexcept {
         return without_network_;
     }
 
-    const bool& engine::parameters::without_graphics() const noexcept {
+    bool engine::parameters::without_graphics() const noexcept {
         return without_graphics_;
     }
 
diff --git a/sources/enduro2d/high/starter.cpp b/sources/enduro2d/high/starter.cpp
index 0ffede87..0a693b0f 100644
--- a/sources/enduro2d/high/starter.cpp
+++ b/sources/enduro2d/high/starter.cpp
@@ -116,46 +116,65 @@ namespace e2d
         return true;
     }
 
+    //
+    // starter::library_parameters
+    //
+
+    starter::library_parameters& starter::library_parameters::root(url value) noexcept {
+        root_ = std::move(value);
+        return *this;
+    }
+
+    url& starter::library_parameters::root() noexcept {
+        return root_;
+    }
+
+    const url& starter::library_parameters::root() const noexcept {
+        return root_;
+    }
+
     //
     // starter::parameters
     //
 
-    starter::parameters::parameters(const engine::parameters& engine_params)
-    : engine_params_(engine_params) {}
+    starter::parameters::parameters(engine::parameters engine_params) noexcept
+    : engine_params_(std::move(engine_params)) {}
 
-    starter::parameters& starter::parameters::library_root(const url& value) {
-        library_root_ = value;
+    starter::parameters& starter::parameters::engine_params(engine::parameters value) noexcept {
+        engine_params_ = std::move(value);
         return *this;
     }
 
-    starter::parameters& starter::parameters::engine_params(const engine::parameters& value) {
-        engine_params_ = value;
+    starter::parameters& starter::parameters::library_params(library_parameters value) noexcept {
+        library_params_ = std::move(value);
         return *this;
     }
 
-    url& starter::parameters::library_root() noexcept {
-        return library_root_;
-    }
-
     engine::parameters& starter::parameters::engine_params() noexcept {
         return engine_params_;
     }
 
-    const url& starter::parameters::library_root() const noexcept {
-        return library_root_;
+    starter::library_parameters& starter::parameters::library_params() noexcept {
+        return library_params_;
     }
 
     const engine::parameters& starter::parameters::engine_params() const noexcept {
         return engine_params_;
     }
 
+    const starter::library_parameters& starter::parameters::library_params() const noexcept {
+        return library_params_;
+    }
+
     //
     // starter
     //
 
     starter::starter(int argc, char *argv[], const parameters& params) {
-        safe_module_initialize<engine>(argc, argv, params.engine_params());
-        safe_module_initialize<luasol>();
+        safe_module_initialize<engine>(
+            argc, argv,
+            params.engine_params());
+
         safe_module_initialize<factory>()
             .register_component<actor>("actor")
             .register_component<behaviour>("behaviour")
@@ -172,7 +191,12 @@ namespace e2d
             .register_component<spine_player_cmd>("spine_player_cmd")
             .register_component<spine_player_evt>("spine_player_evt")
             .register_component<sprite_renderer>("sprite_renderer");
-        safe_module_initialize<library>(params.library_root(), the<deferrer>());
+
+        safe_module_initialize<library>(
+            params.library_params().root());
+
+        safe_module_initialize<luasol>();
+
         safe_module_initialize<world>();
     }
 
@@ -180,9 +204,9 @@ namespace e2d
         the<luasol>().collect_garbage();
 
         modules::shutdown<world>();
+        modules::shutdown<luasol>();
         modules::shutdown<library>();
         modules::shutdown<factory>();
-        modules::shutdown<luasol>();
         modules::shutdown<engine>();
     }