Knock the Prophet of Regret out of his throne

1. Get Sputnik Skull

2. Play through the level regret on any diffuculty

3. Get any explosive weapons you can find. Needler and Fuel Rod Cannon works best.

4. Blast Regret with all of your fire power until his gravity throne flips over.

5. Watch regret as he helplessly shoots his plasma pistol at you. He will teleport after 10 seconds back to his gravity throne.

6. Good luck and have fun!

Note: If you kill regret after you blow him out of his gravity throne he will drop the plasma pistol he used trying to kill you.