Game Development Systems (Engines)
There are dozens of game development engines, each with its own affordances. A link to an annotated list of game engines follows this paragraph. This page will emphasize four game engines that may be especially useful to teach game development to students and teachers as well as to develop learning games for desktop and mobile devices: Stencyl, Scratch, Construct 2, and Unity. To see more game design systems, click the link below or visit my earlier (some info outdated) Game Design Arcade resource page at http://mentalarcade.com/game/.
Annotated Short List of (mostly) Free Game Engines:
Scratch: Totally free, simple programming environment that can be used to learn game design and programming. "Stand-alone" games and mobile games can't be programmed through Scratch. Games can be played through the Scratch program (for Mac, Windows, Linux, and possibly Android) or through a Flash version of the game embedded in a Web page. Scratch uses snap-together program tiles to define behavior, and its programming system is used in Stencyl (below) and several other development systems. Scratch is used in thousands of schools and is, by far, the most common environment for education on this page. Visit my Scratch Programming page at http://MentalArcade.com/games/scratch.html for tutorials and examples. Here's a 30-minute talk by Scratch developer Mitch Resnick on the learning ideas behind the Scratch system: http://www.youtube.com/watch?v=yDPssJedOJ4
Stencyl: Stencyl offers a powerful, free development system for Mac and Windows but requires a paid version to convert to HTML5 and mobile platforms. Stencyl uses a combination of codeless dialog boxes like GameSalad and snap-together program tiles like Scratch to give it both ease of use and customizability. Stencyl can also show the underlying Objective C programming code that it produces, and programmers can customize further using Objective C. Stencyl seems to offer a highly flexible approach to meet the needs of new game designers as well as more accomplished programmers. Popular games in Apple's and Google's app stores have been programmed in Stencyl.
Construct 2: Develop only on Windows, need paid version to export to HTML5 and mobile devices. Highly regarded engine can make a variety of game types with an interface similar to GameSalad. Free version is limited in features, but school licenses are inexpensive ($50/month for unlimited licences).
Unity: Specializes in developing 3D immersive games. VERY powerful game engine but with a steeper learning curve. Games require more power to run, particularly on mobile devices. The free version of Unity converts games to mobile formats at no extra cost! The Harvard educational games designed under Chris Dede are often programmed in Unity. Playmaker is a paid add-on to Unity that speeds program development and uses drag-and-drop programming rather than traditional program coding.
The bottom line is that Scratch is an ideal introductory learning environment, Stencyl is focused on the game developer with intermediate skills, and Unity is for a game developer already familiar with programming. Scratch games can be easily shared, but are played within the Scratch environment or within a web page. Stencyl games can be played free as Flash apps, and with a paid license, Stencyl games can run natively on Windows, Mac, iOS, Android, and HTML5. Sophisticated, immersive, 3D games can be developed at no cost in Unity for any platform. The Playmaker extension for Unity simplifies programming but adds a cost.
Your path may begin with Scratch, move to Stencyl to see a development system focused ONLY on games, and then possibly to Unity if your programming skills are well beyond beginner. Each system is a fantastic environment for learning, and Stencyl and Unity are excellent for game development.
Finally, you should know about ARIS, a different kind of game development system where you use a simple system to create a "locative," mobile game. That means the game is played in a specific location like Times Square, the Washington D.C. Mall, or possibly with a building like an art museum or a school. ARIS games are played through the ARIS mobile app. No programming is needed, but the kinds of games are extremely limited. Developed at the University of Wisconsin, Madison, ARIS is totally free to develop and use.