Here is the full list of all 12 BloodRayne Betrayal achievements.
Find the hidden idol
Kick open the Coffin Rocket 20 times
Activate BloodRayne: Betrayal's alternate soundtrack
Complete the game
Chain-explode 5 enemies
Kill 5 enemies with a single gunshot
Collect all the ancient vampire skulls
Finish every level with the ranking "Dhampir"
Hop on 50 heads in a row without touching the ground
Complete any level while taking no damage
Defeat Crab Puncher without getting hit
Kill 250 enemies with environmental hazards