Jam Sessions is a new, digital musical instrument that is every bit as innovative as Toshio Iwai's Tenori-On, with the added benefit of making sense to someone other than Toshio Iwai. It is endlessly configurable, ridiculously feature-rich, and easy to operate. It is potentially useful for traveling musicians, but is just as enjoyable for amateurs who just want to mess around and make some impromptu music.
Jam Sessions lets you make noise by holding a direction on the d-pad corresponding to a labeled guitar chord and then dragging the stylus across a bar on the touch screen to strum. Up-strokes and down-strokes sound different, as they would on a real guitar. Developer Plato painstakingly recorded samples of up-strokes and down-strokes for each chord, and the effort results in a startlingly realistic sound, which is just different enough from a real guitar to be interesting. The speed and intensity of your strum affects the volume of the sound, as well. Strumming is intuitive and fun, and sets off some lovely visual flourishes on the screen. A tutorial teaches you how to use this system when you first turn on the game; you can revisit the tutorial at any time.
There are endless options for changing the sound and experience of the game. There are plenty of cosmetic changes like background images and the color and shape of the strum bar, and it is enjoyable to 'skin' your instrument to your liking. The strum bar effects can be pretty mesmerizing. There are also more significant options for customization. You can create your own palette of eight chords out of 120 (plus eight more assigned to the L button plus a direction) and save multiple palettes. You can apply six effects to your sound using simulated distortion, flange, chorus, and other pedals, all with appropriate dials, and even save your preset combinations of such effects. You can alter the direction of your up-strokes and down-strokes, change the manner in which the game registers a muted strum, tune the guitar, and set different volumes for different areas of the screen.
As for judging whether or not it's worth a purchase, that's also difficult. If you think you'd have a good time playing your DS like a musical instrument, this is absolutely worth your money. If you aren't interested in music, do not purchase this product. While it may surprise interested parties by being more full-featured than expected, it's not going to win over anyone looking for a traditional game or anything other than an innovative way to play music. It is exactly what it seems. It is an astoundingly well-designed musical instrument, with a simple interface, but it is still a musical instrument. One that we find satisfying to play with.
Final Score: 9/10