Killer Escape 4 continues the series but also starts something new .
There's about 30 mins gameplay if you figure it all out quickly and don't find look for any of the 10 crystals or read any of the 10 notes
There's also a couple of Awards for completing it quickly etc that unlock a little more info about what's going on.

Killer Escape 4 is an FPEG - A First Person Escape Game - cool eh?
It's essentially a Point & Click FPS game with the primary goal of escaping. (So expect a little reading & puzzling ;-))