Here is the full list of all 18 Unplugged achievements.
FirstGig
Get a Golden Record in Steel Panther - Eyes of a Panther
Unlock The Broom
Unlock Schecter Blue Ocean
Unlock Schecter Astro
Complete all the third album challenges.
Complete all the second album challenges.
Complete all the first album challenges.
Retune successfully 50 strings
Play all the songs in all the campaign albums successfully
Score 1 Million points in a song
Score 500k in a song
Score 100k in a song
Get 100k Fans
Get 10K Fans
Finish your first song in H-A-R-D
Get your first 1000 Fans