Unlocking Characters
You can play as some famous musicians and characters in the game by first beating them during the boss battles and then buying them in the Shop. You can buy Slash and Tom Morello for $10,000 each. Lou, the personification of the devil, sells for $15,000. Once you buy these characters, you can play as them in the game.
Cheat Codes
Go into the cheat menu from the title screen and enter these codes to activate cheats. Unlock all songs for use in Quick Play with the code "Yellow + Orange," "Red + "Blue," "Red + Orange," "Green + Blue," "Red + Yellow," "Yellow + Orange," "Red + Yellow," "Blue + Red," "Yellow + Green," "Yellow + Green," "Blue + Yellow," "Blue + Yellow," "Orange + Yellow," + "Orange + Yellow," "Yellow + Blue," "Yellow," "Red," "Yellow + Red," "Red," "Yellow," Orange." Prevent yourself from failing in a song with the No Fail code, which is "Green + Red," "Blue," "Red + Green," "Yellow + Green," "Blue," "Yellow + Green," "Red + Yellow," "Orange," "Red + Yellow," "Yellow + Green," "Yellow," "Yellow + Green," "Red + Green."
Mastering Higher Difficulties
Most players have little trouble perfecting the game on Easy mode because this difficulty level only requires you to hit the red, green and yellow notes. Medium mode adds the blue note and requires the use of your pinkie. Hard mode incorporates the orange note to use all five frets on the neck of the virtual guitar. This means you must slide your fingers up and down the neck to hit all of the differently colored notes. Most players find that it's more natural to use their index finger than their pinkies. Therefore, you will likely see more success on the Hard and Expert difficulty modes by keeping your index finger on the red fret and your pinkie on the orange fret and sliding your hand to the left and back to the right as needed. This means you use your pinkie only for the orange notes, while the index finger hits the red and green notes.
Beating the Bosses
The boss battles include power-ups that you earn by hitting several power notes in a row when they appear. These include such things as causing your opponent's difficulty to increase, making his screen shake and making him hit his whammy bar several times before he can play another note. The best way to beat the bosses is to overload them with power-ups. Instead of using a power-up as soon as you get, it wait until you have two or three saved up and hit him with them simultaneously.