These are my firsts interactions with the game engine, and with a game engine in general. 

It parts from a sample of the engine itself, where you have a box definning a floor. Next evolution was creating a Room, so by just creating additional boxes with different sizes and locations, we had our Tunnel comformed.

Next it was the Players.... Boxes again, and things they fire... spheres (just another model ready to use from the samples...)

On a second round of experiments, you check other in examples about elements to incorporate. Among these would be the particle emissions to define the fire flare, and as well the ribbons to give the elements such movement sensation.