GameMaker: Studio and Developing Cross-Platform Games
One of the first things you need to think about before you start making your game on GameMaker: Studio is where and how people are going to play it. Are you making an HTML5 game that people can play on your website?
Do you want to make a game that you can submit for inclusion in Apple’s App Store, or Google Play, or even for use on the Sony PS4 or Vita?
Whatever your goal, you need to know the differences between the platforms, such as which code will work where. In addition, you need to be aware of scaling and resolution issues — for example, will your heads-up display (HUD) be just as legible on a large monitor as it will on a handheld device?
You also need to keep in mind how you want the controls to work. For PC games, you probably have keyboard and mouse controls. For a mobile device, you need to think about taps, swipes, and pinching and zooming.
Start with a specific platform and develop your game toward that one platform. Don’t try to make your game work perfectly on all platforms all at once. Try developing your game to work on Windows first — that should also work just fine on both iOS and Android platforms.