To unlock the Nemesis 13 Guitar, complete Co-Op Career Mode on any difficulty.

To battle with Lou using Easy Mode notes, try the following. When the battle with Lou begins (on Expert Mode), strum without holding any frets down. When you lose, select the Tutorial option at the Game Over menu. Do the Guitar Battle Tutorial and play through it in its entirety. After the "Lesson Complete" message appears on-screen and the next fret board appears, pause the game and exit. This will bring you back to the Lessons menu.

From here, press the red button, which will bring you back to the list of songs. The battle with Lou should be highlighted. Choose the song, and Lou’s note chart will be set to Easy Mode now. Your note chart will still be in Expert Mode, but Lou’s will be in easy mode.

You can unlock Tom Morello (of Rage Against the Machine), Slash (of Guns N Roses/Velvet Revolver), Lou (the Devil in the game), and a character called MetalHead by beating them in the game and then purchasing them for $10,000 (Lou costs $15,000).

To unlock the Saint George guitar, complete Career Mode on Medium.

To unlock the Moon Shot guitar, complete Career Mode on Easy.

The following songs can be unlocked in the game:

To unlock Precision Mode, insert the following notes in the Options menu: Green & Red x3, Red & Yellow x2, Red & Blue x2, Yellow & Blue, Yellow & Orange, Yellow & Orange, Green & Red x3, Red & Yellow x2, Red & Blue x2, Yellow & Blue, Yellow & Orange x2.

To unlock all of the game’s songs for Quick Play Mode, insert the following notes in the Options menu: Yellow & Orange, Red & Blue, Red & Orange, Green & Blue, Red & Yellow, Yellow & Orange, Red & Yellow, Red & Blue, Green & Yellow x2, Yellow & Blue x2, Yellow & Orange x2, Yellow & Blue, Yellow, Red, Red & Yellow, Red, Yellow, Orange.

To unlock Hyperspeed, go to the in-game cheat menu (found under Options) and insert the following cheat on your guitar: Orange, Blue, Orange, Yellow, Orange, Blue, Orange, Yellow.

Head into the Option menu and head towards Cheats. Then, insert the follow password to ensure that you can’t fail a song: Red & Orange, Blue & Yellow, Orange & Green, Yellow & Red x3, Yellow, Red, Blue, Orange, Green, Green & Red, Blue, Green, Orange, Red & Blue x2.