How Does it Work (4 out of 5)
No add-ons, no touchscreen, no microphone, Rock Band Uplugged is a Rock Band game with a difference, but it will also appear very familiar if you've played Rock Band 2, as this is essentially a cut down, handheld version of that game that borrows a lot of its soundtrack. The idea of Rock Band Unplugged is to keep each instrument playing by itself, which you do by successfully completing a phase of notes for that instrument. Once you complete a phase, use the shoulder buttons to flip to another instrument and carry on playing. If you miss a note though, the phase restarts and the other instruments won't wait for you, so you'll have to keep an eye on which ones are failing. There are only four notes to worry about (even on Expert), and you use the up, left, triangle and circle buttons to play them, so the buttons you need are always under your thumb. You can use X or down to deploy overdrive, which you might need to help save any failing instruments.
Playability (5 out of 5)
The game itself is very similar to Rock Band 2, there's a Quickplay option where you can play any of your unlocked songs, Training explains how the game works and there are a few other options to customize the game to your liking. The main bulk of the game takes place in the Tour option, where you have to play songs to earn fans to unlock more venues to play more songs to, etc… As with Rock Band 2 there are several songs per venue, as well as random/custom/mystery setlists, although this does mean (especially early in the game) you tend to have to play a lot of songs more than once. I think that Rock Band Unplugged is designed to be more of a "quick go" sort of game, than a prolonged session, so this shouldn't cause too many people an issue. Hopefully there are a few songs you'll enjoy playing more than once.
Graphics and Sound (4 out of 5)
It has to be said, Rock Band Unplugged is visually very impressive, and stands up well compared to its big screen relatives. It's easy to see which instruments you need to move to next, and the addition of a solid line between paired notes helps distinguish between notes that need to be played together and notes that are slightly one after the other.
The game comes with over 40 tracks on the UMD, many of which you may already be familiar with from other Rock Band or Guitar Hero games, and there are over 50 tracks available for purchase from the PlayStation store (although it seems unlikely there will be any more).
The Verdict (5 out of 5)
Although the game is a couple of years old now, Rock Band Unplugged for the PSP still stands up as a good example of portable entertainment. It only takes five minutes to turn it on and play a quick song, but it's easy to get sucked in and keep playing for hours.