Unity is a flexible and powerful development platform for creating multiplatform 3D and 2D games and interactive experiences. It's a complete ecosystem for anyone who aims to build a business on creating high-end content and connecting to their most loyal and enthusiastic players and customers.
Construct 2 is a powerful ground breaking HTML5 game creator designed specifically for 2D games, developed by Scirra Ltd. It allows anyone to build games quickly in a drag-and-drop fashion using a visual editor and a behavior-based logic system — no coding required!
The Unreal Engine is a game engine developed by Epic Games. It is a complete suite of game development tools made by game developers, for game developers. From 2D mobile games to console blockbusters and VR, Unreal Engine gives you everything you need to start, ship, grow and stand out from the crowd.
Cocos2d-x is an open source game engine under MIT license. It can be used to build games, apps and other cross platform GUI based interactive programs.
Cocos2d-x has been widely used by individuals and enthusiasts as well as big companies.