Instructions
Play through the game until you have unlocked all of the possible fillers and finishers. Fillers are designed to damage your victims without killing them -- although it is possible to kill them using a filler if you don't keep a close eye on their health -- while finishers are meant to kill your victims in a variety of increasingly painful ways. A good way to get enough points to unlock extra content is to press "X" to compress the room enough to cause your victims pain, but not enough to kill them.
Press "Z" to decompress the room just before your victims die. Press "Shift" to give them a boost of adrenaline once you've unlocked that option to give them extra health; however, you can only use this a few times before your victims die of an adrenaline overdose. You can also leave your victims alone for a few minutes, during which time their health slowly returns. This lets you start the torture over again, increasing your points significantly.
Torture the victims as much as possible before using a finishing move. These finishers give you large amounts of points, but they also finish the level. Use adrenaline when appropriate to keep the victims alive, and back off of the torture for a few minutes to let them fully heal. You can repeat this process as long as you'd like until you finish them off with a finisher that gives you significant amounts of points. For example, the Scarabs finisher gives you more than 5,000 points.