Purgeatory is a game about seeking to balance heaven and hell. Gameplay is split between three levels (Heaven, Earth and Hell).
As players kill the respective forces of good and evil their karma goes up or down (killing angels and priests lowers your karma, killing satanists or demons raise your karma).
Earth
Players begin gameplay on earth. Your goal on earth is to either make it to heaven or hell so that you can kill each side's stronger. Players must now kill either priests or satanists until their karma levels qualify them to enter heaven or hell. Rounds last 30 second, if a player is unable to qualify for either heaven or hell, the game is over.
Players begin on Earth. There, Priests and Satanist are infesting the world.
Heaven
The player has killed enough satanist and due to significant karma has entered Heaven. However, now that the player is in heaven, the only way out is to get back to earth. To do this, you must lower your karma to the hell level. So killing angels is the name of the game. Kill enough and you get to go back to earth. If you cannot get back to earth and get stuck in heaven at the end of the round, heaven has won.
Hell
The player has killed enough priests and due to significantly low karma has entered Hell. However, now that the player is in hell, the only way out is to get back to earth. To do this, you must increase your karma to the heaven level. So killing demons (and other evil creatures) is the name of the game. Kill enough and you get to go back to earth. If you cannot get back to earth and get stuck in hell at the end of the round, hell has won.
Score
Eventually, players are slowly given less and less time on each level until eventually they will not be able to go back and forth. Being stuck on any level will result in a loss. Bonus points are rewarded for successive kills that are inline with your karma. Thus players have the choice of potentially digging themselves a bigger hole and potentially more points, or play it safe and have a very low score when they hit the time threshold.