diff --git a/apps/amethyst/.envrc b/.envrc
similarity index 100%
rename from apps/amethyst/.envrc
rename to .envrc
diff --git a/apps/amethyst/lib/api/game.ex b/apps/amethyst/lib/api/game.ex
index cdfa36d..a9c5c03 100644
--- a/apps/amethyst/lib/api/game.ex
+++ b/apps/amethyst/lib/api/game.ex
@@ -36,21 +36,23 @@ defmodule Amethyst.API.Game do
           Amethyst.GameRegistry.register(__MODULE__, unquote(meta))
           Process.sleep(:infinity)
         end
-        def start(state) do
-          loop(state)
-        end
-        defp loop(state) do
-          receive do
-            {:login, caller, cfg} ->
-              case login(caller, cfg, state) do
-                {:ok, state} ->
-                  send(caller, :ok)
-                  loop(state)
-                {:refuse, state} ->
-                  send(caller, :refuse)
-                  loop(state)
-              end
-          end
+    end
+  end
+
+  @spec start(Amethyst.API.Game, term()) :: no_return()
+  def start(mod, state) do
+    loop(mod, state)
+  end
+  defp loop(mod, state) do
+    receive do
+      {:login, caller, cfg} ->
+        case mod.login(caller, cfg, state) do
+          {:ok, state} ->
+            send(caller, :ok)
+            loop(mod, state)
+          {:refuse, state} ->
+            send(caller, :refuse)
+            loop(mod, state)
         end
     end
   end
diff --git a/apps/amethyst/lib/apps/game_coordinator.ex b/apps/amethyst/lib/apps/game_coordinator.ex
index b1dceb3..bdc6158 100644
--- a/apps/amethyst/lib/apps/game_coordinator.ex
+++ b/apps/amethyst/lib/apps/game_coordinator.ex
@@ -54,7 +54,7 @@ defmodule Amethyst.GameCoordinator do
 
   defp _create(type, games) do
     state = type.instantiate()
-    pid = spawn(type, :start, [state])
+    pid = spawn(Amethyst.API.Game, :start, [type, state])
     games = [{type, pid, []} | games]
     {pid, games}
   end
diff --git a/apps/amethyst/lib/apps/game_registry.ex b/apps/amethyst/lib/apps/game_registry.ex
index 2b626ea..cd9a575 100644
--- a/apps/amethyst/lib/apps/game_registry.ex
+++ b/apps/amethyst/lib/apps/game_registry.ex
@@ -30,9 +30,10 @@ defmodule Amethyst.GameRegistry do
   @impl true
   def handle_call({:register, module, meta}, _, state) do
     if Keyword.get(meta, :default, false) && find_default(state) != nil do
-      {:reply, :error, :default_exists}
+      {:reply, {:error, :default_exists}, state}
+    else
+      {:reply, :ok, [{module, meta} | state]}
     end
-    {:reply, :ok, [{module, meta} | state]}
   end
 
   @impl true
diff --git a/apps/amethyst/test/game_registry_test.exs b/apps/amethyst/test/game_registry_test.exs
new file mode 100644
index 0000000..e54a89e
--- /dev/null
+++ b/apps/amethyst/test/game_registry_test.exs
@@ -0,0 +1,33 @@
+defmodule GameRegistryTest do
+  use ExUnit.Case, async: true
+
+  @moduledoc """
+  This module includes tests for Amethyst.GameRegistry
+  """
+
+  test "Register a game" do
+    Amethyst.GameRegistry.register(:fake_game, [:some_meta])
+    assert Amethyst.GameRegistry.list() |> Enum.member?({:fake_game, [:some_meta]})
+  end
+
+  test "Register many games" do
+    Range.new(0, 50) |> Enum.map(fn game ->
+      game = String.to_atom("game#{game}")
+      Amethyst.GameRegistry.register(game, [])
+      game
+    end) |> Enum.map(fn game ->
+      assert Amethyst.GameRegistry.list() |> Enum.member?({game, []})
+    end)
+  end
+
+  test "Register and get default game" do
+    Amethyst.GameRegistry.register(:fake_game, [default: true])
+    assert Amethyst.GameRegistry.get_default() == {:fake_game, [default: true]}
+  end
+
+  test "Fail to register multiple games" do
+    Amethyst.GameRegistry.register(:fake_game, [default: true])
+    assert Amethyst.GameRegistry.register(:other_game, [default: true]) == {:error, :default_exists}
+    assert Amethyst.GameRegistry.get_default() == {:fake_game, [default: true]}
+  end
+end
diff --git a/apps/example_game/lib/example/game.ex b/apps/example_game/lib/example/game.ex
index e8163a3..9093165 100644
--- a/apps/example_game/lib/example/game.ex
+++ b/apps/example_game/lib/example/game.ex
@@ -9,7 +9,7 @@ defmodule Example.Game do
 
   @impl true
   def login(from, cfg, state) do
-    Logger.debug("Player logged in from #{inspect(from)}: #{inspect(cfg)}")
+    Logger.info("Player logged in from #{inspect(from)}: #{inspect(cfg)}")
     {:ok, state}
   end
 end
diff --git a/apps/example_game/test/test_helper.exs b/apps/example_game/test/test_helper.exs
deleted file mode 100644
index 869559e..0000000
--- a/apps/example_game/test/test_helper.exs
+++ /dev/null
@@ -1 +0,0 @@
-ExUnit.start()