Frets on Fire is one of those games that promote carpal tunnel syndrome. It requires you to fixate on a small selection of keys and spam them to kingdom come according to visual instructions, which are shown in real time. You know Guitar Hero, right? Frets on Fire is the same thing, more or less.
Frets on Fire uses seven keys to simulate playing guitar. By default, you use the F1 through F5 keys to pluck the frets and Enter and Right Shift to picking and alt-pick. As you might expect, the five frets are color coded but, unless you re-bind, paint, and practice with the fret keys, you will most likely suck at playing Frets on Fire.
Coincidentally, the "friendly" German impersonating character voice that introduces the game concept during the Tutorial conveys the same message. It's not like you need a tutorial to understand the gameplay, but if you enjoy a patronizing voice that's insulting you no matter how well you perform, go right ahead.
You can attempt playing one of the three songs included in Frets of Fire. These all have three difficulty levels. The difference between levels consists of the number of instructions per squared inch. Missing to hit and hold the right keys at the right time will lower your score and puts out an annoying screech, to make sure you got the message.
However, this is where the technical problems start. Error screeching sounds do not play no matter the settings. Also whenever you change some setting, Frets on Fire performs a fatal crash to the desktop. The settings get saved, but you will need to launch it every time you change something, which is annoying.
Another thing that bugged me is the graphical component. Frets on Fire does not display a lavish set of decors and fret effects, but then again, considering it's free, I wouldn't see this as a problem per se. However, the result is not only dull, but the effects also obstruct essential gameplay information. While a fret pinch indicator lights up to white when you press its key, the marker does the same if you hit it, reducing the contrast between it and the background, making it difficult to spot its length, and thus, confusing.
Frets on Fire allows you to edit existing songs and also to add new songs in Ogg Vorbis format. However, I could not add any new songs, as FoF's file browser refused to pick up the OGG file. There's also an option to import original Guitar Hero songs, but I didn't bother trying that one.
Considering that Frets on Fire is a free rip-off of Guitar Hero, I was reasonably excited at first. However, the cringy and insulting tutorial managed to quell my enthusiasm. Then, the visual and technical problems that I faced sealed the deal. Instead, I'd purchase the commercial game. Guitar Hero costs a pretty dime, but at least it features more songs, fewer if any technical issues and, finally it does not insult new players.