I've played Rock Band Unplugged for PSP. No, it did not involve holding a tiny plastic guitar.Although Unplugged has all the trappings of the four-player music game, the gameplay is quite different.  All four musical parts are shown on screen, and you flip back and forth between them, playing everything all at once.How's that possible? Well, each song is separated into short phrases of a few notes each. Nail a phrase perfectly and that part of the song will start to play itself for a little while, so you can flip to the next part. The game will show you which part to jump to next to keep your perfect combo score going. There's a bit of a learning curve, but once you get the controls down, it's a musical experience that feels quite a bit different from the elaborate home game, but with its own appeal.Long-time fans of Rock Band maker Harmonix will have already figured out that Unplugged is actually a throwback to Frequency and Amplitude, the PlayStation 2 games that the developer created back when Guitar Hero was just a twinkle in Alex Rigopulos' eye. It feels quite a bit like Amplitude, and I know this because I just went back and took the old game for a spin to refresh my memory. It's all there: Jumping between "lanes" that define each part of a song, having to nail each phrase before the part will play itself, scoring combo moves by jumping to the right lane immediately after completing a phrase. Only now you're playing rock songs like "Buddy Holly" and "More Than a Feeling," as well as a few tracks that will be available exclusively on this PSP game first, before showing up on the console Rock Band's download store:3 Doors Down- "Kryptonite"AFI- "Miss Murder"Alice in Chains- "Would?"Audioslave- "Gasoline"Black Tide- "Show Me the Way"Blink 182- "What's My Age Again"Freezepop- "Less Talk More Rokk"Jackson 5- "ABC"Tenacious D- "Rock Your Socks" Rock Band Unplugged for PSP lets you play drum, vocal, guitar, and bass tracks for 40 different songs using the handheld console's ...