In contrast to the awful horror adventure from Zoetrope Interactive, Darkness Within, developer Frictional Games has got it right. The Penumbra series, comprised of two parts – Overture, released in early 2007, and the recently-released Black Plague – not only manages to terrify, but also introduces some excellent new innovations not seen in the genre.

Overture gets the ball rolling with a bang. You play the role of Phillip who, after receiving a mysterious letter, sets off to Greenland to track down his missing father. It isn’t long before Phillip finds the hatch to his father’s research base, built on top of an old mine, and then becomes trapped inside. Here, the atmospheric, finely-plotted adventure game begins in earnest, as Phillip pieces together the history of the abandoned mine, solves a string of logical, interesting puzzles, and battles a small army of rabid dogs.

Penumbra’s control scheme, which relies on Frictional Games’ slick physics engine, sets it apart from other genre games. To interact with the environment, you’ll need to use the mouse to emulate a physical action: To open a door, you grab hold of the handle and arc the mouse toward you; to throw an object, you flick the mouse in the right direction you want it to go. When it works, the control scheme is an incredibly immersive gameplay device, but when it doesn’t, the game almost falls apart. Combat is main the culprit here, because rather than simply pressing a button to attack an enemy, you’ll instead need to swing an object. More often than not, your view also swings wildly, making combat – and any action sequence in the game – messy, inelegant, and a stark departure from the moodiness of the game’s exploratory puzzle-solving segments.

Fortunately, Black Plague puts things right. It picks up right where Overture left off, introduces some new characters, plot twists, and ‘mind tricks’, and more importantly, removes all combat from the game. In fact, it seems like the developers were so determined to remove any semblance of combat that you won’t find a single weapon. Without the combat, you’re left with an excellent adventure game that sees you hiding and outsmarting enemies – just as a terrified physicist trapped in an abandoned mine would do – and gives you more space to enjoy the slowly unfolding mystery.

The combined price tag for both games is pricey, particularly given the relatively short four hours of gameplay in each game, but what you get for the money is quite easily one of the best adventure horror games out there. If you still think $42 is too much to pay for only eight hours of gameplay, we’d recommend waiting for the inevitable bundle pack, which will likely let you play them back-to-back – just as it should be.