To challenge myself I created a 3D browser game PADDLE. The challenge here was to optimize the game to run smoothly on most browsers, especially when it is rendering in 3D.
Try it out at mkkl.dk/paddle
The game is about juggling a ping pong ball with various paddles that you unlock by getting high scores. The design process was mostly focused on creating a pleasing and understandable UI inspired by high end gold/black aesthetics, and getting the game to run in a browser.