This is the program I use to make games. It is rather easy to learn, but it still has a lot of potential for advanced 2D gaming. 3D is possible, but it’s not the main focus. If you want to make 2D games, though, this is definitely a program to check out.
The offer to get the Standard version for free has now expired.
Games made with this program include Hotline Miami – which has been a hit on Steam – as well as Spelunky and Stealth Bastard. Check out the game showcase at the offical GM:S website here: