Fuzion is the name for Hero Gmaes and R. Talsorian Games metasystem RPG rules. it offers a great variety in its rules and since the game mechanics work the same no matter the genre, it can be used to play in a great many types of gaming environments from fantasy to sci-fi, to anime (duh) with little modification. What little rules modifications that are needed are handled in plug-ins, rule sets that augment and add to the core rules, but in a way so as to preserve the general mechanics of the system.

In other words, Fuzion is a set of rules that can be used in nearly any genre just by adding in some rules to balance out the game mechanics so they better capture the feel of that genre. Instead of one massive, giant system that is made to try and cover everything, Fuzion is a small, simple system whose various rules plug-ins allow the GM to fine tune them for a specific genre and add any level of complexity he wishes to have in his game.