Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Have You Seen His Grades? (5 points): Complete a tutorial level.
It's Alive (5 points): Unlock Eddie's Frankenstein guitar.
Ouch! (5 points): Create a custom tattoo.
Intruder (10 points): Complete the career intro.
Van Halen (10 points): Complete a career on Beginner. (Band or Solo)
Every Band Wants Some!! (10 points): Complete a song with the full band. (4 player band)
They Ran With the Devil (10 points): All band members get a 50 note streak at the same time. (4 player band)
Somebody Get Them a Doctor (10 points): Hit 100% of the notes in a song as a band. (4 player band)
Atomic Power Punk (10 points): All band members activate Star Power at the same time. (4 player band)
Hung High (10 points): All band members earn an 8x multiplier at the same time. (4 player band)
EVH (10 points): Unlock all of the Van Halen instruments.
The Broken Combs (15 points): Complete a gig in West Hollywood.
Ain't Talkin' 'Bout Dallas (15 points): Complete a gig in Dallas.
Far Away Lands (15 points): Complete gigs in London and The Netherlands.
The Space Brothers (15 points): Complete gigs in Los Angeles and Rome.
Van Halen II (15 points): Complete a career on Easy. (Band or Solo)
Jump (15 points): Complete all Van Halen songs. (Band or Solo Career)
Rock Out Big Cities (20 points): Complete gigs in Berlin and New York City.
Unchained (20 points): Unlock all Van Halen characters.
Women and Children First (25 points): Complete a career on Medium. (Band or Solo)
Fair Warning (35 points): Complete a career on Hard. (Band or Solo)
The Tour is Ending (35 points): Complete a majority of the gigs. (Band or Solo)
Diver Down (45 points): Complete a career on Expert. (Band or Solo)
1984 (55 points): Complete a career on Expert+. (Solo Drum)
The Woodshed (60 points): 5 star guitar for 'Little Guitars', 'Cathedral', 'Spanish Fly', and 'Eruption'. (expert)
316 (65 points): 5 star all Van Halen songs on Bass Career. (expert)
Diamond in the Rough (70 points): 5 star all Van Halen songs on Vocal Career. (expert)
Double Bass Master (75 points): 5 star all Van Halen songs on Drum Career. (expert)
Guitar God (100 points): 5 star all Van Halen songs on Guitar Career. (expert)
5150 (100 points): Complete all Van Halen songs on every instrument. (Guitar, Bass, Drums, and Vocals)

Additionally, there are sixteen secret achievements:

Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (5 points): Unknown.
Secret achievement (10 points): Unknown.
Secret achievement (10 points): Unknown.
Secret achievement (10 points): Unknown.
Secret achievement (10 points): Unknown.
Secret achievement (15 points): Unknown.