This was a prototype game we made at Hidden to develop an advanced physics system.
The system was designed to dynamically create physics objects in real-time only as and when they were needed. It would do this by essentially subdividing (or splitting) live physics objects into new incrementally smaller pieces wherever an explosion took place. This meant that physics calculations were kept to a minimum because there weren't actually as many physics objects as it would appear, and there were rarely more than a few collisions taking place at any one time. This gave us enormous speed gains, especially on mobile devices.