The reason why you have to add scoring in your game is because whenever the player plays your game they would like to know how many points they got. So when I first started adding scoring it was a little hard and long. But the main thing you have to do in adding scoring is that you have to put the code in. If you don't add a code your character might not move or your score will get higher and higher. So for my scoring the character has to touch the collectable in order to get a score even though I only got 9 collectables the character still gets a even score in the game.
