Preview: 'Doctor Who: Blood Of The Cybermen'

It turns out that people rather like Doctor Who. The first episode in the downloadable episodic series City Of The Daleks managed an incredible half a million downloads in just under two weeks. Regardless of its freebie status, that's some achievement for any episodic project, and not the type to rest on their laurels the folks at Sumo Digital and the BBC have been busy preparing the second episode - focused around Cybermen and set within snowy Arctic wastes - for release this weekend.

While the core conceit of the first episode was a relentless series of stealth sections, Blood Of the Cybermen is pleasingly more varied, with exploration and investigation elements peppered throughout. The opening drops you in a scenario not unlike one of Charles Cecil's adventure games: The Doctor and Amy follow a distress beacon and, perched on a cliff top, have to rescue a skidoo rider trapped at the bottom of a cave. While the solution is quite frankly a simple one - a discarded rope is tied to the skidoo to heave him up, while The Doctor has to revive him with a canteen of warm spring water - inside the first five minutes it asks more of your item selection and environmental knowhow than anything seen from the entirety of the first episode.

Of course things don't quite go to plan, so The Doctor has to find a way out with his new rider friend in tow. The icy cavern comprises a series of ledges that require jumping across, as well as blocks to push and moving platforms to observe (which are well worth falling off for hilarity's sake) that are rather obvious in design but again pleasant enough to undertake. Once you're back at the Tardis, The Doctor and Amy take off to a geological base to discover why the rider was fleeing for his life in the first place.

It's here that we get a first proper look at the new adversaries. The base is under the control of Cyberslaves, researchers whose flesh is turned into metal and who appear as jumpsuited humans with tin-can heads, as well as the floor-dwelling Cybermats, which are worm-like creatures that have infested the air vents and are responsible for this whole transformation mess in the first place. Facing the Cyberslaves in a handful of staged encounters is typical action-game fodder, as The Doctor or Amy avoid the marching foe while turning on steam vents or live electrical circuits before they are eventually downed. These sections are surprisingly tense - made even more so thanks to the slightly rigid tank controls that can restrict your movement - and feel far more threatening than any of the Daleks you bumped into last time.

Access through the base is slowly opened up as you find keycodes and components, allowing you to converse with its surviving residents and understand what exactly went on. It's a lot of back and forth in terms of taking these objects to where they should be, but the base's compact layout and frequent switching between Doctor and assistant makes it an enjoyable romp. It also expands some of the existing mechanics in these new settings, with new mini-games of matching wavelengths and creating organic components, more dialogue trees and a script that adds a little more humour this time round, throwing in the sentence "Doctor of the flaming obvious" as well as a reference to Die Hard.

The final act is riddled with sentries patrolling linear corridors, and resorts back to the basic stealth gameplay that we've seen previously, which is tight on timing and occasionally frustrating but serves as an understandable way to ramp up the challenge before it all comes to a close. Although the lack of polish that was so noticeable in the first chapter still remains, it's pleasantly surprising to see such a shift in theme and activity so soon after its debut, so much so that it may even sway those deterred from the opening's linearity. Once again it's free for British licence fee payers and most certainly worth digging into on a lazy Sunday afternoon, and we hope the developers will to continue to create fresh and exciting scenarios from here on in.

Blood Of The Cybermen will be available for free from June 26 for PC users, with a Mac version available shortly afterward.