The game system in DC Heroes is sometimes called the Mayfair Exponential Game System (or MEGS). DC Heroes uses a logarithmic scale for character attributes. For example, a value of 3 is double a value of 2 and four times a value of 1. The scale allows characters of wildly different power levels to co-exist within the same game without one completely dominating a given area.
The third edition was a single book rather than a boxed set and had several rules enhancements.