Clickteam Fusion has been around in various guises since 1993, with their latest offering Clickteam Fusion 2.5 now having a free version to create code free 2D games which you can publish to many different platforms including Steam, the iOS app store and Android app store.
Clickteam Fusion 2.5 free edition allows you to make games in HTML5 for easy sharing with friends, and has Box2D built in, meaning 2D physics based games (such as Angry Birds) are really easy to make. Following the tutorials you should be able to make your first game in less than an hour.
- Watch a simple platformer tutorial video by Almighty Zen Taco to get started.
- Get the tool here.