The idea of letting users create and play their own Guitar Hero Style songs seems like a good idea, but the Windows version of the game suffers from some design flaws that make it nearly unplayable.
Frets on Fire -- An Open Source Guitar Hero Clone
An open source Guitar Hero clone might seem like a good idea that could be a lot of fun. Such a thing does exist. A PC user can download Frets on Fire from th Source Forge web site. Users can download Windows, Macintosh, and Linux versions.
Frets on Fire allows the user to play user generated songs in a Guitar Hero style fashion. The controls are similar although the graphics leave a little to be desired. The graphics are often incidental in the Guitar Hero Game. The most important thing for the player is being able to see the notes as they fly by. For those looking for a free version of the popular Activision franched, the author recommends to continue looking. The developpers of this game meant well, but the game doesn't play smoothly. Playing smoothly is critcial for a music game.
The Tutorial Portion
The tutorial provides a good introduction to the game, but the phony German accent of the narrator quickly becomes annoying. The narration uses the word suck gratuitously and uses "s---" in one part of the narration (interestingly, they censor the subtitltes, so kids can learn to say it but not spell it). If the Frets on Fire programmers intended people of all ages to use this application, they will need to clean up the narration.
How the Game Plays
The game never makes it clear exactly when it expects a note to be pressed, and the game itself seems to suffer from some lag issues. The lag may be a function on the Windows version of Frets on Fire that is not present in the Linux and Mac OS versions of the game. The user never knows when exactly he should press the function and enter key combination that allows him to play a note. Notes seem to change on the screen without warning, making the process of 'playing' a song guesswork. (I can confirm the laggy feeling in Windows, even if you have the rhythym down and know when to hit notes, despite the lack of a good graphical cue, the game will often tell you that you got it wrong -Ed.)
Frets on Fire's Good Points
The flexibility of Frets on Fire should be its major selling point.. Unfortunately, its design flaws detract from what might be an enjoyable game if the programmers fix the game’s slow response time and ambiguities.
Recommendation: Wait for the Sourceforge Team to Work Out the Bugs
Rating 
The Frets on Fire development tem deserves credit for creating a Guitar Hero like game for the personal computer. The good pars of the game end there. The open source community produces many high quality software pieces. This Guitar Hero clone does not belong on that list on the moment.
Bugs and design flaws in open source programs get corrected quickly because anyone who knows how to code can contribute to them or modify it for their own needs. The open nature of this program and its flexibility in allowing users to download songs means it might be a good program if other coders can fix its issues.
Editor's Note: I hate to hammer something like this, and would probably have given Fretts on Fire a two personally. If someone can fix that laggy feeling, give the player a clear indication of when the approaching notes should be played, and narrate the tutorial in a more appropriate fashion, the game's an easy hit. The idea of open source song libraries has incredible appeal, but the inability to get the key presses right is obviously not an ignorable flaw in a music game.
Author's Note: Despite its flaws, Frets on Fire is a good idea. He hopes people in the open source community will fix the issues in the Windows version of the game.