Added aliens and glow on the numbers

Alien.gd

@@ -0,0 +1,34 @@
+extends CharacterBody2D
+
+class_name Alien
+
+signal alien_died(value : int)
+
+@export var hits : int = 5
+@export var points : int = 500
+
+func _ready() -> void:
+	$Sprite2D.play("default")
+	move_random()
+
+func move_random() -> void:
+	velocity = Vector2(randf() - 0.5, randf() - 0.5).normalized() * 30
+	get_tree().create_timer(randf() * 3).timeout.connect(move_random)
+
+func _physics_process(delta: float) -> void:
+	if position.y < 28:
+		position.y += delta * 30
+	else:
+		move_and_slide()
+
+func hit() -> void:
+	hits -= 1
+	if hits <= 0:
+		alien_died.emit(points)
+		get_parent().call_deferred("remove_child", self)
+		call_deferred("queue_free")	
+	else:
+		$AlienSound.play()
+		var tween = get_tree().create_tween()
+		$Sprite2D.modulate = Color(1, 1, 1, 0)
+		tween.tween_property($Sprite2D, "modulate", Color(1, 1, 1, 1), 0.3)