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