This document discusses animation options for a mobile tower defense game with 500+ characters. It considers fully 3D animation but finds it too resource intensive. 2D animation is explored but only allows rendering in one direction. 2.5D animation is proposed as a solution, using graphical effects to make 2D animations appear 3D and allowing rendering in multiple directions. Key advantages noted are reusing animations across characters and creating a 3D feeling while maintaining simple graphics requirements and speed.