Games are nice, but there's a lot more you can do with a console than work towards a predefined goal achieved through arbitrary rules. Jam Sessions turns the DS into a guitar simulator, complete with a wide variety of effects and audio toys, and it's not hurt in the slightest by the lack of anything that could be called a game. It's a combination of tool and toy that's just plain fun, either to mess around or create with.
A thick line runs across the center of the touch screen, and running the stylus across it produces the sound of strumming a guitar. A slow strum is quieter than a fast one, and strumming up or down produces slightly different sounds within the same chord. A chord is chosen with the plus pad, and different ones can be assigned to each of the eight directions plus another eight accessible by using the trigger as a shift key. So, at any one time, sixteen different notes are available with up or down strumming variations and full control over note intensity, which should be enough for just about any composition.
Like any good tool, though, the amount of enjoyment gotten from Jam Sessions is going to be directly related to how much work goes in.
Despite the basics being almost instantly accessible, once you place the notes in an easily memorable pattern it's still a pretty complex music production system. Helping with the learning curve are Jam Sessions's tutorials, songs, and drills. The basic "do this" instructions are supplemented by an Ear Training mode that runs through strings of notes and expects you to reproduce them, which is a great way to get a feel for the sounds. The included songs are also more tutorial than game, due to there being no real way to fail in playing them. Everything in Jam Sessions is there to guide the player to the Free Play mode, which is unstructured and all about creation.
Free Play is exactly what it sounds like, a mode completely open for experimentation and performing. Edit the notes on the plus pad to your heart's content, play around with effects to get that crunchy reverb sound, and save your best creations using the Record function. Jam Sessions is designed to turn the DS into a fully-functioning musical instrument, and there are a surprising number of audio editing options buried in the various menus.
Like any good tool, though, the amount of enjoyment gotten from Jam Sessions is going to be directly related to how much work goes in. Music takes effort, and if you're as musical as I am then it'll be hard to take the game past the "Ooh, pretty sounds!" stage. Creativity isn't easy, and nobody gets a free ride to being talented. Those willing to put in the time, however, will find Jam Sessions to be something that won't replace a real guitar any time soon, but still ends up as a fun and creative musical toy.