After the rise of D&D as a hobby, other people realized the potential of role-playing games and there was an explosion of systems in the late 70’s/early 80’s. One such system was Champions.
Instead of a fantasy setting, Champions modeled 4-color comic book scenarios. And the approach it took was pretty different from D&D. Instead of a menu of options available to players, Champions offered a toolkit so that players could make whatever they wanted. It was a generic system intended to model anything the players or GM needed.
The core feature that makes the game soar is the special effect/mechanics divide. Where the look and feel of a power is a part of how it is written up for most games (think the flames of D&D’s Burning Hands spell), the specific look and feel of a power in Champions is completely separate from how it functions in the system.
If I were building a character with lightning based powers and another with ice based powers, I might give the former a devastating lightning bolt that he can hurl at enemies. The ice based hero might get an arctic blast that she can use to freeze things solid.
In game terms, mechanics, these work the same way. They are both what is called an energy blast. The difference is that the player decides what that blast looks like, which has an effect on play.
There are a couple of ways this affects play. An ice beam will hit the target, leaving them with small ice crystals across the point of impact. A lightning bolt might burn a neat hole in the clothes the target is wearing, and set his hair on end.
If the ice hero fights someone with fire powers, and they both have an energy blast that is mechanically the same, by the game rules they would cancel each other out.
I adore this system. You can model almost anything with the combination of mechanics and special effect.
Some time after Champions was released they tweaked the system so it could be used as a universal system. This was released as the HERO System. You can run science fiction, horror, fantasy, pulp, etc.
So, HERO System has a few drawbacks. The first is that there is a learning curve. Like GURPS (another universal system), HERO System has a lot of moving parts.
The other drawback is time. Building things can be time consuming. Building an entire campaign’s worth of material can be a difficult obstacle to overcome. To help, there are lots and lots of sourcebooks with prebuilt enemies, allies, items, etc.
Still, I love this system. Being able to model anything is nice, but there’s something freeing about being that much more in control over the game. I dunno. Maybe I like punching bad guys through brick walls.