Add in-app purchasing to my existing game and make it scalable to any iPhone screen size.

Hi! I have written a game mainly in swift and I need someone to implement in-app purchasing for it. There will be 4 in-app purchases: 1. Spray - When the user clicks "Spray", all the enemies will reverse their paths and move away from the player 2. Blood - When user clicks "Blood", a drop of blood goes on the screen where the player is and all the bees become attracted to that drop for 10 seconds. After 10 seconds they go back to following player 3. Shield - Already half implemented. When the player clicks "Shield" a shield goes around the player for 10 seconds. The bees hit this shield and cant get past it. Their path changes 4. Ghost - Already implemented. When a user clicks the ghost button, they go invisible for 5 seconds and cannot be hit in this time. You must also: - Make the game scalable to any iPhone screen size. - Currently only scaled for iPhone 6. Must work on 4/4s, 5/5s, 6 and 6 plus.