Basically Rock Band in a portable format except no plastic instruments or singing into a mic, you need to constantly switch between instruments (tracks) a la Harmonix's earliest rhythm games Frequency and Amplitude, and NO MULTIPLAYER.
The way the instrument switching works is you play a particular instrument and if you successfully complete a "phrase" that instrument will play on its own for a while so you then switch to another track, play that phrase, and repeat. There's an "Extras" mode where you can play just the instrument(s) you want but on the World Tour mode, which is just like the World Tour mode on the non-portable systems, instrument switching is mandatory.
I'm mediocre at best at rhythm games but I found the difficulty levels well-suited for my skills. Easy is almost snooze inducing. Hard is doable for most of the songs and Expert I fail a lot at. The portable version feels similar to its bigger brothers in that it's not trying to be the most difficult rhythm game out there, though I've heard some of the DLC tracks are very difficult. The controls are what you would expect for this type of game and are completely customizable if you don't like the defaults. Aside from the annoying Triangle Circle combo the hardest part of the controls for me is activating Overdrive without screwing up the incoming notes. I definitely miss not being able to "tilt" my instrument to activate that.
The song selection is just okay to me (song list here
) as there are only a handful of songs I like enough to keep playing over and over. It does have two of my favorite rock songs of all time, though (which oddly enough I used to be able to play on a real guitar) so that was enough to keep me happy for a while after "finishing" the World Tour mode.
As mentioned up top there's no multiplayer in this game, not even ad hoc mode, which boggles the mind given the game's ancestry. That doesn't matter to me as there's nobody around me I would play it with even if it did but this glaring omission may keep some of you from buying the game.
Without the instrument controllers and multiplayer Rock Band Unplugged loses much of the feel of Rock Band, which basically redefined the party game genre, but as portable rhythm games go it's still fun to play, assuming you like enough of the songs.
Rating: Buy It, if you like the song selection and don't care about the lack of MP