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