Ents is a library for aiding in creating games where you create your game objects through composition. No more creating classes, no more messy update logic, no more rendering coupled to a specific graphics library. You add components to your Entities (i.e. position, velocity, size, angle, image), controllers (i.e. user input, physics, networking, AI), and a view. Ents is designed to promote modular development, you are no longer creating a sprite which has physics, you are defining Entities that can have position and velocity, and you create a Physics controller that takes velocity and adds it to position. There are many features in Ents you can ignore, it's not going to strap you down to how it wants to be used.