User Summary:
A half-angel, half-demon named Belial is able to break out of his prison after Lucifer is defeated (as per the plot of the first game), and is out for revenge. He wishes to kill the angel Sammael who had a hand in his imprisonment, but to that, he has to break out of Hell first...
This standalone continuation of the original game changes the main character and the weaponry the player can use, along with some of the enemies and the enviroments - all that while keeping the original gameplay intact. Overdose is therefore a single-minded shooter in which the player defeats hordes of enemies, and it does not have any riddles or looking for keys or anything of that sort.