Into the third dimension!
You already live in a world with three dimensions. You can walk forward and backward, side to side, and jump up or duck. The reality of three dimensions becomes even more apparent if you are flying or even swimming.
Most 2D games operate by allowing the player to move left and right, or jump up or down. This is what we did when we created RoboRacer2D. In this type of 2D game, the missing dimension is depth. Our Robot could not move further away from us or closer to us. Considering that we were drawing him on a flat screen, it shouldn't be too surprising that he was limited to two dimensions.
Simulating 3D
Of course, artists found a way around this limitation hundreds of years ago by observing that as an object gets farther away from us, it gets smaller, and as it gets closer to us it gets larger. So, a simple way to represent 3D in a 2D world is to simply draw the more distant objects as smaller objects. 2D games learned this trick early on and used it to simulate...