Relativity is a milestone in custom content as it allows mappers to create environments where they have complete control over gravity for the first time ever in an Unreal engine game. The map is primarily a showcase of this system, but also features solid gameplay and well-themed design. The development kit gives mappers all the tools they need to create their own environments with ease, and coders the ability to extend it for their own mod's custom weapon projectiles.

This work stems from a mutator previously prototyped which allowed for walking on all surfaces in standard UT2004 maps.