We've mentioned already Painkiller is a big name in the shooter world, so we're curious to see if the upcoming PC title Painkiller: Resurrection, developed by an amateur studio, will do the series justice. Enough of trailers and screenshots (see below) though, a demo is available today so you can see for yourself.
It's a 1.4GB download for the game's single-player mode, and curiously, comes in ISO format, typically one pirates (tsk, tsk) will be familiar with. Anyhow, you'll need a virtual disk program to load it (unless you'd prefer to burn it) -- we recommend the wonderful and free Virtual CloneDrive.
You can grab the demo through the source, and the full game this November.