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 second edition is reputed to have the following changes:replaced gadget rules, added new powers, added new skills, add the concept of advantages, variable power cost, and the "Post Crisis" DCU.