Coin animation

When you created the Coin scene, you added an AnimatedSprite, but it isn't playing yet. The coin animation displays a shimmer effect traveling across the face of the coin. If all the coins display this at the same time, it will look too regular, so each coin needs a small random delay in its animation.

First, click on the AnimatedSprite and then on the Frames resource. Make sure Loop is set to Off and that Speed is set to 12.

Add a Timer node to the Coin scene, and add this code to _ready():

$Timer.wait_time = rand_range(3, 8)
$Timer.start()

Now, connect the timeout() signal from the Timer and add this:

func _on_Timer_timeout():
    $AnimatedSprite.frame = 0
    $AnimatedSprite.play()

Try running the game and watching for the coins to animate. It's a nice visual effect for a very small amount of effort. You'll notice a lot of effects like this in professional games. Though very subtle, the visual appeal makes for a much more pleasing experience.

The preceding Powerup object has a similar animation that you can add in the same manner.