A kids' guide to coding simple games using CSS and JavaScript.The multiethnic group of Ruby, Markus, Grace, Rusty, and their cat mascot, Scratch, invites readers to help them as they prepare five different games for a hackathon in which they will compete against their rival, SaberTooth Studios. The types of games are tic-tac-toe (called "noughts and crosses," to align with the British creator's website), a snake game, table tennis, an endless-runner game similar to Temple Run, and a side-scrolling platformer (think: Super Mario). Each lesson takes readers through it one game component at a time, ultimately building the code to double-page spreads that display the full code for each game at the end of its chapter. These lessons do a good job of contextualizing and explaining how the code functions as well as showing how much code goes into even the most basic of games. The Get Coding website is also referenced throughout as a resource for the activities and a source for some components of the final game (the shortest chapter of the book). The hackathon storyline, however, feels tacked on and provides little benefit—the premise is repeated a couple of times and then resolves off-page between chapters 4 and 5. The design helps break down explanatory text and walls of code into manageable chunks (though the escalating complexity of code may intimidate some beginners), and the illustrations will be full color. Along with an index, there's an introduction with an efficient history of computer games.An ambitious coder's new best friend. (Nonfiction. 10-14)