diff --git a/configure b/configure
index f6d52a3179..5c32856325 100755
--- a/configure
+++ b/configure
@@ -113,6 +113,10 @@ def build_type(args):
         ret = 'Debug'
     elif mode == 'release':
         ret = 'Release'
+    elif mode == 'relwithdebinfo':
+        ret = 'RelWithDebInfo'
+    elif mode == 'minsizerel':
+        ret = 'MinSizeRel'
 
     return {
         "build_type": ret
@@ -355,7 +359,7 @@ def parse_args():
         formatter_class=argparse.ArgumentDefaultsHelpFormatter)
 
     cli.add_argument("--mode", "-m",
-                     choices=["debug", "release"],
+                     choices=["debug", "release", "relwithdebinfo", "minsizerel"],
                      default=getenv("BUILDMODE", default="debug"),
                      help="controls cmake build mode")
     cli.add_argument("--optimize", "-O",
diff --git a/libopenage/engine/engine.cpp b/libopenage/engine/engine.cpp
index c3a9985986..9af6d4fe89 100644
--- a/libopenage/engine/engine.cpp
+++ b/libopenage/engine/engine.cpp
@@ -32,32 +32,28 @@ Engine::Engine(mode mode,
 	// time loop
 	this->time_loop = std::make_shared<time::TimeLoop>();
 
+	// game simulation
+	// this is run in the main thread
 	this->simulation = std::make_shared<gamestate::GameSimulation>(this->root_dir,
 	                                                               this->cvar_manager,
 	                                                               this->time_loop);
 	this->simulation->set_modpacks(mods);
 
+	// presenter (optional)
 	if (this->run_mode == mode::FULL) {
 		this->presenter = std::make_shared<presenter::Presenter>(this->root_dir,
 		                                                         this->simulation,
 		                                                         this->time_loop);
 	}
 
+	// spawn thread to run time loop
 	this->threads.emplace_back([&]() {
 		this->time_loop->run();
 
 		this->time_loop.reset();
 	});
-	this->threads.emplace_back([&]() {
-		this->simulation->run();
-
-		this->simulation.reset();
-
-		if (this->run_mode != mode::FULL) {
-			this->running = false;
-		}
-	});
 
+	// if presenter is used, run it in a separate thread
 	if (this->run_mode == mode::FULL) {
 		this->threads.emplace_back([&]() {
 			this->presenter->run(debug_graphics);
@@ -69,13 +65,18 @@ Engine::Engine(mode mode,
 		});
 	}
 
-	log::log(INFO << "Created " << this->threads.size() << " threads"
-	              << " (" << std::jthread::hardware_concurrency() << " available)");
+	log::log(INFO << "Using " << this->threads.size() + 1 << " threads "
+	              << "(" << std::jthread::hardware_concurrency() << " available)");
 }
 
 void Engine::loop() {
-	while (this->running) {
-		// TODO
+	// Run the main game simulation loop:
+	this->simulation->run();
+
+	// After stopping, clean up the simulation
+	this->simulation.reset();
+	if (this->run_mode != mode::FULL) {
+		this->running = false;
 	}
 }