The The Dark Knight Pack Add-on for LEGO Batman 3: Beyond Gotham has 5 achievements worth 50 gamerscore.
Complete the Dark Knight level with all Minikits unlocked
Complete the Dark Knight level
Complete the Dark Knight level after achieving True Hero status
Defeat Batman (Dark Knight Trilogy) as the Joker (Nurse) character
Set both Free Play characters as Bane (Dark Knight Rises) and Scarecrow (Batman Begins)