Here is the full list of all 12 Yar's Revenge achievements.
Kill (1000) enemies with missiles
Kill 20 or more enemies in one shot with the Zorlon Cannon
Beat a level without taking damage on Normal or Hard
Get your multiplier above 100 on Normal or Hard
Complete all levels in Hardcore Mode
Beat a level in Hardcore Mode without dying
Beat the game without dying on Normal or Hard
Beat the game using only the pulse laser on Normal or Hard
Defeated Queen Raktamalina
Beat every level in Co-Op Mode
Beat a boss using only the pulse laser on Normal or Hard
Kill (500) enemies with the railgun