The number of digital devices and their species is increasing, which represents an increasing challenge in the information and communications industry. The number of applications raises every day more and more, with a significant percentage of applications which are computer games that are present on almost all platforms. Developers needed to meet demands of the market, where is a significant number of different device types, so they began to develop multi-platform tools that offer the possibility of rapid development of applications for a variety of digital devices. In this paper is presented one multi-platform tool designed for developing computer games called Unity. Unity allows development of computer games for all popular platforms used by a wide range of devices. The paper also provides an insight into the methodology and development of two-dimensional multiplatform games that have experienced the reemergence of the popularization with smart phones and they number is increasing. Through the chapter it is present the emergence and evolution of Unity tools throughout history, the basics of working within the Unity graphic user interface, and concrete development of 2D game Space Invaders, which upon completion can be installed on Windows, Andorid, iOS and Windows Phone 8 platform. Finally, the conclusion describes the results obtained from the use of multi-platform development tool.