Exp system implementation (not yet affecting stats)

src/game/Game.cs

@@ -173,6 +173,12 @@ public partial class Game : Node3D, IGame
   }
 
   private void OnEnemyDefeated(Vector3 vector, EnemyStatResource resource)
+  {
+    GameRepo.PlayerData.SetCurrentExp(GameRepo.PlayerData.CurrentExp.Value + resource.ExpFromDefeat);
+    DropRestorative(vector);
+  }
+
+  private void DropRestorative(Vector3 vector)
   {
     var restorativeScene = GD.Load<PackedScene>("res://src/items/restorative/Restorative.tscn");
     var restorative = restorativeScene.Instantiate<Restorative>();