Whether it's the classic PC original, the recent Hollywood movie, or even the slightly alarmist press coverage it's garnered over the years, we're going to assume you've heard of Doom. We're also going to assume that you probably have certain expectations of any game or film attached to the title, namely that it'll include exploring mazes and shooting at monsters, that there's plenty of blood and gore and that the experience is scary, yet somehow intensely entertaining. The good news is that Doom RPG delivers on all these expectations; even better news is that it adds a few neat twists of its own.
The basic setup will be instantly familiar to any Doom fan: you play a marine who's been sent to a research centre on Mars to investigate some strange goings on. It rapidly becomes clear that these goings on involve the release of hordes of unearthly demons which now freely roam the corridors and tunnels of the research centre, and that your role is essentially to 'clean up', dispatching the dark denizens with the aid of an increasingly powerful arsenal of weapons through 10 ever-tougher levels. The first-person viewpoint (you can see the weapon clutched in the hands of your marine) is identical to the original PC version and both demons and weaponry borrow heavily (albeit with a few additions like the brutal axe and the fire extinguisher) so you'll be able to employ all the old favourites such as super-shotgun, rocket launcher and the BFG to dispatch bull demons, fiery skulls and hell barons.
However, whilst the basic plot and goal remain the same, the means by which you get there are crucially different - after all, this is a role-playing game and not an all-action shooter. Consequently, in place of the non-stop shoot-n-move approach, everything is broken up into turns. Each movement, conversation or action (e.g. firing a weapon) essentially takes up one turn, so that combat becomes a matter of firing, waiting for the enemy to retaliate and then deciding whether to fire again or simply move out of harm's way. What might sound slightly cumbersome in our explanation actually works faultlessly in execution and fits incredibly well with the mobile format. The action can still progress fluidly if you make decisions quickly (indeed, at times you can forget that it's not all done in real-time), but the pace of the game is under your control so there's also the option to take time out, heal yourself with a medikit, check the map and select a different weapon before rejoining the fray.
The role-playing element goes further than combat though, with the ability to use credits collected throughout the game to boost your character's vital statistics (such as health and accuracy) as well as buy additional weaponry. Though it's not essential to your enjoyment (your levels will increase naturally as you clear levels and kill demons, and most weaponry can be picked up as you go) it does add an extra dimension and a way to measure your progress.
The presence of multiple secondary characters and interactive computer systems is similarly welcome, providing additional puzzle elements (for example, you need to locate the pass codes for doors) as well as spinning an intriguing X-files-esque sub-story about factions within the establishment and their role in the arrival of the demons. Just as importantly, these interactions also add to the wicked humour that underpins the game, with witty asides and classic character catchphrases.
The only casualty of the role-playing approach is the game's tension. Where the PC and Xbox versions have never faltered in their ability to genuinely terrify, here you'll barely receive more than a slight scare, as although the demons still look pretty fearsome as they loom into sight in a tight corridor or appear on all sides from an unwittingly sprung trap, the curious lack of sound coupled with the ability to effectively put them on pause robs them of their menace.
Whilst fans will justifiably mourn this downgrading of the fear factor and will hope for the restoration of some unearthly audio in the inevitable follow up, from our point of view this is an incredibly small price to pay for a great mobile version of a truly exceptional game.