Here's me beating it, without cheats, on hard.
Step 1: Cheat Codes
Enter these in the options menu.No fail doesnt work in solo career mode so you have to use it in quick play. After Hyperspeed is activated highlight it and press the green button until the number next to it says 5. All songs will not show up in the cheats screen but you will get a message that its on.
Step 2: Play It Like a Monkey!
Your friends should all be around you saying no way he and/or she cant do this. (Dont worry you wont fail in the first 5 seconds, you have no fail on.) When it first starts, get a gorilla grip on the strum bar, and press those buttons and strum like Buckethead after 40 red bulls! its about 8 minutes long and youll probably need to take a break in the middle of it to rest your arms.After you finish the song, go get your clothes changed because youll be really sweaty if you Strum like I do.