Wikipedia
Fuzion is a generic role-playing game system created by the collaboration of R. Talsorian Games and Hero Games. The rights to Fuzion are jointly held by Mike Pondsmith of R. Talsorian Games, along with Steve Peterson and Ray Greer of Hero Games. Fuzion is a combination of the Interlock System, (used in games like Mekton and Cyberpunk 2020), and the HERO system (used in Champions, Justice, Inc., Star Hero, etc.). Fuzion is an adaptable system which can be played in any genre and setting imaginable.
Fuzion is noted for its anime-genre support, customizable rules flexibility, and being one of the first generic game systems to be released for free over the internet. It is one of the first games to readily allow licensing, albeit not the "hands-off" licensing offered by the Open Gaming License (OGL) that came about some years later. A modified OGL set of rules based on Fuzion is published by Gold Rush Games as the Action! System.
There are two versions of Fuzion that have been published: the simplified Instant Fuzion, and more detailed Total Fuzion (also known as Primary Fuzion). A third, Maximum Fuzion, was hinted at in Fuzion-based Bubblegum Crisis RPG, but has never been published.