The design of this game is based on a decent sized tile map, 50 tiles wide and 50 tiles high. Our basic tile size (non-Retina) is 32 x 32 pixels. We will implement the tile map as a single scrolling layer, keeping our hero centered on the screen (except near the edges, but we'll get to that). The goal of the hero is to pick up three goal "signposts" scattered around the map. There will also be health power-ups on the map to restore the hero's health. We want to have two types of enemies. The first will move in a straight path toward the hero. The second type will be a little smarter. When they run into an impassable wall, we will use an A* Pathfinding algorithm to find a way around the wall, and then revert to the same straight line toward the hero logic. The player will be able to control the hero using either an on-screen joystick or tilt controls. With either method, there will be a fire button on-screen to shoot. We will break out our game into three layers for easier...