I would say no, its not ok. Its like when people play with the Ouija boards, they involve witchcraft and demons. I would think computer games that glorifies demons would fall into the same category. The Bible clearly condemns occultic activity and sorcery.
Here are some scriptures about "Occult Practices":
Deuteronomy 18:12-14 says "Let no one be found among you who sacrifices his son or daughter in the fire, who practices divination or sorcery, interprets omens, engages in witchcraft, or casts spells, or who is a medium or spiritist or who consults the dead. Anyone who does these things is detestable to the LORD, and because of these detestable practices the LORD your God will drive out those nations before you".
Acts 19:19 says that "A number who had practiced sorcery brought their scrolls together and burned them publicly. When they calculated the value of the scrolls, the total came to fifty thousand drachmas. Note: a drachma was a silver coin worth about a day’s wages".
But most of all 1st Thessalonians 5:22 warns "Abstain from all appearance of evil".
-Anonymous