The proprietary engine being developed by Imperium Studios for all of their current and future projects. It utilizes the DirectX Graphics library for 2D/3D graphics, XACT for Audio, Tiled QT for world/level design, and includes many custom features created by the Imperium Studios Development Team.
A couple of screenshots showing off a couple of features that the engine supports. The biggest feature is the developer console that allows you to change and manipulate game and engine settings in real time.