Painkiller

Although many gamers who have not played the games are aware of the Painkiller franchise, not many are aware of the Painkiller, the weapon for which the game is named. It is the default weapon, the only one which player character Daniel Garner starts the game with, and in keeping with Painkiller's loose association with backstory and plot and such, no explanation is ever given as to where exactly Daniel got his hands on such a strange device. Nevertheless, it is a lot more powerful than you'd expect a starting weapon to be, and the fact that none of its attacks require ammo makes the Painkiller an invaluable part of your arsenal, so it's probably best not to look a gift horse in the mouth. 
 

The Painkiller has three modes of operation. First up is the basic "Pain" mode, the primary fire of the weapon, which sets those three wicked blades on the front a-whirling, allowing you to do to hordes of demons what a weedwhacker does to an unruly lawn. Nasty. The only drawbacks to Pain mode are that it literally requires you to run into your enemies, so if they don't go down quickly, you're likely to take a few hits before they succumb. Not to mention, of course, that using it on enemies with ranged attacks is less than advisable unless you're already in their face.
 
 
 
 
 

Next on the list of the weapon's delightful attacks is the alternate "Killer" mode, which shoots the pointy end of the weapon out as a projectile. Now, you can just shoot this straight into a hapless enemy's face, and indeed, many of the enemies in the game will crumble under just one or two shots, but what this mode is really designed for is the laser wire. Shoot the head into a wall, and it will embed itself there. Then, whenever you point the body of the weapon directly at the head, no matter how far away you are, a laser beam will link the two halves of the Painkiller. This may not seem especially useful, but any enemy who walks into the beam will take some pretty serious damage (that is if they don't just die outright, which is also likely), and since most of the enemies in the game are too stupid to do anything other than run straight at you, this is a handy tool to use against them. The head can be recalled from anywhere in the level (even if solid walls are between you and it) by pressing the alt-fire button again.
 

Finally, the Painkiller features a special combo attack that is amazingly easy to pull off: activate Killer mode while Pain mode is already active (i.e., launch the head while the blades are spinning), and instead of launching straight into whatever's in front of you, it will go flying at your enemies like a whirling propeller of death. Handy! This combo attack (which sadly doesn't have a clever name) is great for filleting enemies you don't want to get close to, although the head moves much slower than it does in Killer mode, so it's not very useful over long ranges unless the enemy has a habit of remaining stationary, such as long-distance projectile launchers. 
 
 
 
The Painkiller appears in the original game, as well as the expansion pack, Painkiller: Battle out of Hell, and the Xbox console port, Painkiller: Hell Wars. Sadly, it does not appear in the sequel, Painkiller: Overdose, but there is a weapon in Overdose which functions identically to the Painkiller, developer Mindware apparently seeing the value of the weapon's razor-sharp love. The weapon re-appears in the questionable sequel Painkiller: Resurrection, in which protagonist "Wild Bill" Sherman describes it as being a "strange object of blades and light", whereupon his mysterious guide explains that the Painkiller is "a weapon for the souls of warriors lost between Heaven and Hell", whatever that means.