Just fixing some typos (#15)

lib/game/enemy.dart

@@ -24,7 +24,7 @@ class Enemy extends SpriteComponent
   // Defaults to vertically downwards.
   Vector2 moveDirection = Vector2(0, 1);
 
-  // Controls for how long enemy should be freezed.
+  // Controls for how long enemy should be frozen.
   late Timer _freezeTimer;
 
   // Holds an object of Random class to generate random numbers.
@@ -128,7 +128,7 @@ class Enemy extends SpriteComponent
     }
   }
 
-  // This method will destory this enemy.
+  // This method will destroy this enemy.
   void destroy() {
     // Ask audio player to play enemy destroy effect.
     game.addCommand(Command<AudioPlayerComponent>(action: (audioPlayer) {

lib/game/game.dart

@@ -57,7 +57,7 @@ class SpacescapeGame extends FlameGame
   // List of commands to be processed in next update.
   final _addLaterCommandList = List<Command>.empty(growable: true);
 
-  // Indicates wheater the game world has been already initilized.
+  // Indicates weather the game world has been already initialized.
   bool _isAlreadyLoaded = false;
 
   // Returns the size of the playable area of the game window.
@@ -67,7 +67,7 @@ class SpacescapeGame extends FlameGame
   // Assets loading and adding component should be done here.
   @override
   Future<void> onLoad() async {
-    // Initilize the game world only one time.
+    // Initialize the game world only one time.
     if (!_isAlreadyLoaded) {
       // Loads and caches all the images for later use.
       await images.loadAll([

lib/game/power_up_manager.dart

@@ -19,7 +19,7 @@ class PowerUpManager extends Component with HasGameReference<SpacescapeGame> {
   late Timer _spawnTimer;
 
   // Controls the amount of time for which this component
-  /// should be freezed when [Freeze] power is activated.
+  /// should be frozen when [Freeze] power is activated.
   late Timer _freezeTimer;
 
   // A random number generator.