Guitar Hero: Metallica

I have the best secret trick/ tip to give you guys. All you have to do is beat the song "The Thing That Should Not Be" on expert difficulty and you get the achievement. You can play the rest of your career on any difficulty.

That song is unlocked once you reach 71 stars so the minimum amount of songs you need to beat is 15 then you can play "The Thing That Should Not Be."

Easy way i found with this once you unlock the last song "The Thing That Should Not Be" go back on expert and play it on bass a very easy song on bass and there you go 75 gamer points

in addition to the expert solo career guides above, you can also one-man band this achievement in BAND CAREER and get both achievements at the same time: Nothing Else Matters and Metallica.

**BE SURE before you start that you check/change the profile you want to attain the achievement is the band leader by going to the preferences screen where you select an instrument, difficulty, etc. then press X (blue button). you should see a coiled blue snake icon above your name indicating that you're the band leader. unfortunately, only one profile, the band leader, can obtain band career achievements.**

Play an instrument on whatever difficulty you’re comfortable with and add beginner's vocals using the mic trick (**see below**). beginner’s vocals will produce plenty of star power to boost your score and easily attain 5 stars per song.

**MIC TRICK: as an alternative to a fan, if you have the right setup, it also works to put the singer's mic into your headphones earpiece (i have full turtlebeach headphones) with the volume up to max and have vocals set to beginner, then turn on your TV sound so you can play along.**

play and obtain all 5 stars in 15 songs until you unlock the ice cave venue (72 stars total). then switch both instruments to Expert and play the final song "The Thing That Should Not Be.” achievements pop up after playing the final song - no need to go and complete all 50+ songs. The final song is easy enough to sing and play at the same time. Expert Vocals and Bass worked for me.

This achievement is actually a lot easier to acquire than it sounds.

You can play through the first 30% of the career on Easy until you unlock the Ice Cavern venue. Than you can just switch difficulties to Expert and beat "The Thing That Should Not Be."

Even if you want to go through the game on Expert you can just beat all the easier songs early on in the setlist and still unlock the Ice Cavern.

If you are going for this achievement and you're not an expert player, just do the Bass career and after getting the required stars to unlock "The Ice Cave" change the difficulty to expert and complete "The Thing That Should Not Be." I'm no expert player and I found it really easy! Happy achievement hunting!

Some people hate to play on lower difficulties than expert. Well dont worry you dont have to play any of the hard songs in the career to finish it. All you have to do is unlock "The Thing That Should Not Be". I have no idea why this is the last song in the game because it is incredibly easy. So just play from the first song and go down the list until you unlock that song. No need to play War Ensemble or Fight Fire With Fire.

The easiest way is to do the glitch mentioned above, I completed the bass career for the "Robert Trujillo" achievement. Just play the final song "The Thing That Should Not Be" on expert, play on bass as it's easier.

play the last song on bass which is the thing that should not be.
play through the game on any difficlty on bass then start the last song.go to the menu and change the diffulcty to expert.its not hard you sould get 3 acheivements... one, mettalica and Robert Trujillo.