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
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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.
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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.
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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.
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Unreal Engine
Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.