The first development from Dr. Nesterov's workshop is a dueling system. Duelists must compete to click on the six numbered discs in the shortest amount of time (an idea taken from a Flash game I saw). The discs must be clicked on in numerical order, and their position and scale is randomised to make things a little more difficult. The HUD is shown below.
A free set, including HUD, basic dueling pistol and instructions are available at my workshop (slurl) - by clicking on the dueling pistol laying on the ground. Also at the workshop is a training dummy to practice against.