Hackmaster is a house system - a set of rules that make up part of a roleplaying game. It includes methods for building a character - a role to be played - and resolving issues around conflicts within that role.
Hackmaster is drawn from a rather large mixed bag of influences, includingby TSR's 2nd Edition AD&D (2D&D), prerelease info on 3rd Edition Dungeons and Dragons (3D&D), Rifts, Rolemaster, Storyteller, and GURPS. In practice, Hackmaster can be seen as evolving piecemeal from 2D&D - starting from the 2D&D Player's Handbook and the Player's Option series, parts of the system are replaced one at a time. In particular, there are three major goals that have driven many of the design choices behind Hackmaster:
The Hackmaster mechanics are medium-complex (bigger than a Storyteller, smaller than a Rolemaster), but hopefully expressive, and provide good methods for continuing advancement and development over the lifetime of the character. Mechanics-wise, emphasis is placed on skills rather than abilities, and all skills should use the same resolution method. As is typical with shiny new house systems, game balance is carefully considered... ...from a respectful distance.
The name `Hackmaster' is taken from the excellent Knights of the Dinner Table; I'm hoping it'll lend a bit of `freewheeling spirit' to my new game. As of this writing, there have been a few vieled references to a Kenzer & Co. Hackmaster RPG, but so far I'm betting that it's still a joke.