Unity3D
Unity is the ultimate game development platform. Use Unity to build high-quality 3D and 2D games, deploy them across mobile, desktop, VR/AR, consoles or the Web, and connect with loyal and enthusiastic players and customers.
21 Alternatives To Unity3D
Armory3D
Armory 3D is a free and open source game development software developed using Haxe and Kha and made to run inside Blender.
Cocos2d-x and Cocos Creator
Cocos Engine Official Website | Cocos Creator | Cocos2d-x | Open Source Cross-Platform Game Development Engine
Construct 2
Scirra Construct is a 2D game development engine with a focus on building games visually.
Esenthel
Advanced collaborative cross-platform game engine, editor, and development environment. Native integration with Nvidia PhysX, Oculus Rift, Facebook, AdMob, Recast Pathfinding, Bullet Physics. Used to create games such as Lucius and Dungeon Hero.
FlatRedBall
Cross-platofrm 2D game engine using C#, focused on developer productivity, transparency, scalability, and ease of use.
JMonkeyEngine
What is jMonkeyEngine? It’s a free, open source game engine, made especially for Java game developers who want to create 3D games using modern technology.
MonoGame
MonoGame is an open source implementation of the Microsoft XNA 4 Framework.
RPG Maker
Make your own PC game with RPG Maker. Our easy to use tools are simple enough for a child, and powerful enough for a developer. Try it free today!
UDK
Unreal Engine 3 is a complete game development framework that operates across 10 platforms. Provides a vast array of core technologies to creating high-quality games and applications.
Unreal Engine
Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.