Ok, so as we said before, the only graphic assets that Buildbox can use are PNG files. If this was just a simple tutorial on how to make Ramblin' Rover we could leave it there. But it's not. Ramblin' Rover is just an example of how a game is made, but we want to give you all of the tools and base-knowledge you need to create all of your own games from scratch. Even if you don't create your own graphic assets, you need to be able to tell anybody creating them for you how you want them...and more importantly, you need to know why.
Graphics are absolutely the most important thing in developing a game. After all, you saw how just some eyes and sneakers made a cute character people want to see move in the previous chapter. Graphics create your world. They create characters that people want to succeed. Most importantly, graphics create the feel of your game, and differentiate it from other games on the market.