Easy, Medium, Hard & Nightmare are the difficulty stages of the game. For stage 'Easy', there are 3 levels. For stage 'Medium', there are 4 levels. For stage 'Hard', there are 5 levels. For stage 'Nightmare', there are 10 levels. Each level being 30 seconds long. Each upgrade is only purchasable five times with an exception for the 'Lazer Level' upgrade- only purchasable 3 times. 'P' to turn music on: Pirates of the Caribbean- He's a Pirate. 'O' to turn music off: Pirates of the Caribbean- He's a Pirate. Boss only for levels 'Hard' and 'Nightmare', stage 5 and 10.
This is my own project, no help. :) Thanks for playing.