End of Nations uses an in-house engine developed by Petroglyph Games, called Alamo. This engine was used in their previous games like Universe at War and (possibly?) Battle for Graxia. The game stores data in .MEG files, which have almost same format as Universe at War. The game uses Trion's patcher/launcher, possibly the same one seen in Rift and Defiance.
Here is minimum system requirements for End of Nations as listed in the official website:
Operating system: Windows XP, Vista, or 7 Processor: 2.0 GHz processor Memory: 2 GB Hard disk space: 6.5 GB available Video card: Shader model 2.0 capable video card Sound: DirectX® 8.1 compliant card DirectX®: 9.0c or better Input: Keyboard, mouse Broadband internet connection: DSL, cable modem, or other high-speed connection
The game also requires DirectX june 2010 update.