Hitman is one of the few titles I can say with any certainty I ‘discovered’. In contrast to Half-Life, a cultural juggernaut of similar vintage that I only arrived at some months after release, Hitman was a game I held in awe from the very beginning. And with good reason: the turn of the millennium was blessed with any number of seminal titles (Deus Ex, most obviously) but few offered much scope for the would-be assassin. Rainbow Six debuted to muted applause, but its tactical thrills were hampered by a deathly tiresome planning phase, and more straightforward fare like Solider of Fortune – if enjoyable in a strictly blood-thirsty sense – could hardly be said to be a competitor at all.

Ostensively a series about the dark moralistic tragedy of determinism, IO Interactive’s Hitman can be pared down to two things: killing targets and getting paid. Little noteworthy about that, you might add, except that in a market flooded with Daikantanas and Heavy Metal: FAKKs – crowing loudly about their majesty, swords, and gargantuan breasts – Hitman was a genuine shot in the arm for traditionalism. With origins in conflict so tragic you can scarcely imagine, there remains little as inherently satisfying as the sniper rifle it made its trademark. That fantasy of calmly walking away from the far away scene of the crime is one Hitman exploited to its fullest; one that Hollywood had played to for many years, and which games had until then only furtively touched upon.

As the first roll of a new property, Hitman: Codename 47 was remarkably successful; doubly so when you consider the formula remained unchanged right through to a fourth title some 6 years later. The titular 47 – whose appearance would come to be as iconic as either Gordon Freeman or Master Chief – was employed by a mysterious cabal known as The Agency, designed as the epitome of blandness and the quintessential contract killing machine. A man of indeterminate ethnicity and few memorable characteristics, who spoke without inflection: witness an early encounter in a Hong Kong restaurant, as he declares “I. need. to. use. the bath. room” with all the monotone charisma of Anton Chigurh. Little did the unflinching bartender realise that his bald customer had designs on a gun he’d placed in the cistern earlier on.

Killing is a serious business, but Hitman wasn’t above indulging homages to iconic pop culture: not just in references to The Godfather but, most famously, Scarface, as you confront a crazed cocaine dealer in deepest Columbia. Like Grand Theft Auto before it, Hitman took its cues from the great and used them to spin its own fiction, revelling in a cinematic scope for violence. Your first assignment had you riding a service elevator to a hit on a Triad rival. Then came a car bombing, made possible by ragdoll physics deployed in their one true purpose: an arms-flailing, opportunistic garrotting that leaves a limo driver slumping helplessly into an exposed sewer.

There was always that balance between gleeful acts of gratification and the kind of expansive, multi-faceted takedowns epitomised by ‘The Lee Hong Assassination’. Although its brief seemed unassuming, the mission quickly silenced any notions of simplicity, opening into an involved operation that had as many paths to success as it did abject failure. You could poison your target by killing a kitchen-hand and stealing his identity, or take a more direct route by shooting through a skylight overlooking the ceremonial banquet. Enterprising players might care to initiate a fire fight in the basement to rescue a CIA agent. Others, to head upstairs and kill a prostitute just because. In Hitman, the only objective was to succeed; exactly how you got there was up to you. Sicko.

Driven though it was by America’s myopic vision of eastern culture, Hong Kong demonstrated Hitman as it could be, just as what followed amounted to what it often was. Missions in Columbia and Rotterdam eschewed playful Hollywood stereotypes for more overtly racist ones: a particularly dire mission saw 47 address the Columbian natives almost as cannibalistic simpletons: “When I get back, you must. show. me. the. way. to. the. drug. lord”. Even the Scarface references betrayed a cultural knowledge relayed chiefly by the liberal use of ‘Marichon’, ‘Amigo’ and ‘Cahoonies’. The levels were equally lacking in substance, home to barren expanses almost entirely incompatible with subversion and infiltration. It felt so far removed from what came before that it was as though a parallel game had been cancelled and plundered for its assets. How else can you explain a mission that sees you inexplicably searching for a sacrifice to distract a hungry jaguar?

‘Traditions of the Trade’ – later revisited in Hitman: Contracts; a tacit acknowledgment that its quality hadn’t been matched since – was a welcome return to tense urban settings, and remains the defining moment of the series. Stalking a luxury hotel, jumping from balcony to balcony to avoid guards and suspicious maids, it was a ticket into a secret-agent fantasy rich with purpose and repeat-offender opportunities. Kill everyone in the hotel, if you like, or quietly finish off your target in the shower. Go nuts and lock a thonged Austrian painter in the sauna; moments have rarely been as dark or as powerfully erotic.

At once stunningly original and unbearably dire, Codename 47 was a flawed masterpiece. For every hotel massacre that served as a barometer for someone’s fan credentials, there were monotonous slogs through Rotterdam that rewarded schlepping through bland, shadowless worlds with having to replay the whole thing again if you screwed up. Even the game’s conclusion failed to muster any enthusiasm for its cause: the knowingly titled ‘Meet Your Brother’ reveals 47′s status as a clone, but the dramatic beats hinge on firepower over precision or considered strategy. After missions in Hong Kong and Budapest that showed remarkable invention, it comes down to IO endlessly spamming you with clones, who you kill with indifference typical of a game tailored to prevent you from identifying with, or caring for, your character.

The sequel, Silent Assassin, arrived to fervent applause best explained by its predecessors chief failing: for all its groundbreaking success, Codename 47 was burdened by an unwieldy control scheme that belied its PC heritage. As the first multiplatform release for the series, Assassin wisely implemented a more controller-friendly configuration that leaned heavily on the kind of context-sensitive controls now ubiquitous in titles such as Splinter Cell. Viewed in that context at least, it is easier to forgive a gaming press being so enraptured by an otherwise disappointing follow-up.

If improved controls did their bit to entice less dexterous players, then generously ‘tweaked’ AI served merely to drive them away again. From the very beginning, a staple of the Hitman experience has been the range of outfits one can use to evade detection: everything from kitchen whites to a garish clown costume have had their day, and the game granted you a certain freedom to (ab)use that system with impunity so long as you were careful with your choices. Silent Assassin took a notably dimmer view of such behaviour. NPCs reacted not just to your outfit, but the manner in which you behaved while wearing it: run when you should be walking, or hold the gaze of a passing guard for too long, and your disguise would be rendered useless. A necessary encumbrance though it may have been to players used to routinely coming out on top, in practice it saw previously methodical strategy devolve into bemused frustration as guards drew weapons at flawless disguises while other times waving you through to the German embassy wearing Bermuda shorts.

Perhaps aware their game had become substantially harder as a result, the developers mitigated the potential for smashed controllers by granting a fallback in the form of save games. As ridiculous concept as it might seem in our world of auto-saving every five paces, Hitman began as an exercise in incremental progress, patiently getting a little further each time until finally unlocking the formula for a perfect run. Of course, what those of us who fetishised 100% completions found to be a masochistic curiosity was, to more sane players, an imposition too far, and it remains a sound concession to this day.

From Sicily to India, Silent Assassin is a bloated production that finds endless utility for non-descript sewers, peppered with exposed manholes like an elaborate game of Whac-a-mole; viewed through a well-earned haze of embittered cynicism, and having once likening them to Valve’s trademark vents suddenly feels like it did them a thematic disservice. The objectives were a familiar blend of assassination and accidental-assassination, carried out to the strains of a storyline that rarely imposed itself beyond references to a missile guidance system you spent the entire game recapturing. The only real point of interest was an unfortunate Japanese torture that saw one barely interesting mission split across four unforgivably dreadful ones. We were teased with endless possibilities, and IO delivered only an escort through a veritable valley of death in the shadow of invisible snipers who could pin you down with impunity from their vantage point in the trees.

There’s plenty to dislike about Silent Assassin – and I haven’t touched on undertakings in Afghanistan that feel more like reflections on the era’s boogie men than anything coherent – but on occasionally it aspires to former glories. The game’s three Malaysian assignments are a fertile opportunity to mix the business of killing with the art of framed break-ins, and India allowed for hold-your-breath moments in a title that gave undue weight to run and gun tactics. Between that and a breathtaking Island fortress finale concerning an unlucky patient on the operating table, Silent Assassin did at least begin to earn its franchise name, if not the praise it received.

2004′s Hitman Contracts was either a response to calls for a faithful update to a beloved game, or a lazy cash-in for an increasingly tired franchise; perhaps both. It had the unenviable task of reshaping old assets into something more than a nostalgic paean to history, and whether or not it succeeds is incumbent largely on having enjoyed Codename 47 – from which Contracts drew its source material – enough to welcome a return, but not so much that you’d resent attempts to rekindle an old fancy.

Much as it remains an easy target for derision, the first half of Contracts consists almost entirely of new material. Forays into Romania and England are fun, picturesque diversions that nonetheless made it clear little had changed, 47′s modus operandi remaining as ever it was. Returning players were thankfully spared further sewer-based excursions, with the finery of an old English manor house marking a welcome return to more hospitable locales, even as the hits themselves felt more tired than ever, rarely deviating from what was by then a well-worn template.

There are seldom few elements in Contracts that can truly be classed as improvements. NPCs return to the previous levels of just-about-there suspicion, and the bloated carcass of Silent Assassin gave way to an economical dozen or so missions. Nevertheless, they were mere revisions to the mean, neither surpassing the innovations made four years previous. The prevailing sense of redundancy is reinforced by the appearance of missions from Codename 47, at least one of which is almost entirely unchanged. ‘Traditions of the Trade’ and ‘The Lee Hong Assassination’ earn their inclusion as long-time fan favourites, and if they are functionally similar to their earlier incarnations, then their powers remain likewise undiminished. They are the archetypical Hitman missions, tactically complex with potent humour, and in their updated guises they demonstrate the franchises’ successes and failures equally well: when one particular level is reproduced with the sole addition of an optional car bombing, you have to wonder if there was even a point, no matter how enjoyable the mission itself.

That is Contracts all over, really: one big question mark over IO’s motivations in releasing a game that, if adequate, has precious little reason to exist. The gameplay specifics, good and bad, survived intact, and the new environments were only sporadically interesting enough to justify calling it a fully-fledged sequel. If anything, it felt more like Codename 47 Special Edition; perhaps that was the intention, and it was just a function of marketing. Whatever the case, there was but one contract of merit – the manor house assassination of Lord Beldingford – and maybe one reason less than that to bother in the first place.

Hitman: Blood Money, meanwhile, was the product of steadier hands brought to bear on a franchise dangerously close to bottoming out. As the fourth instalment in six years, it sought only to evolve a familiar formula by tinkering at the edges, yet emerged as its most refreshing incarnation yet. Blood Money was twelve missions as consistent as they were polished, each a richly observed world in which 47 was distilled to his core functions. The game never strayed from what it did best. There were no ventures to Columbia, no Kayapo tribes, no hijabs or Afghan warlords. It was and is, from start to finish, a pure crystallisation of the Hitman concept.

So much of what failed the sequels was jettisoned or completely overhauled for Blood Money. The levels were the kind of well designed, compact locations the game thrived in: casinos, parties, theatres. A newly upgraded engine brought dynamism to the previously flat and lifeless, with the very first level – the de rigueur interactive tutorial – being a typically lush example of what IO’s artists could now realise, the sun casting long shadows through the harbour railings as the ugly business of killing was at once made beautiful.

It’s true that little was radically different, but then perhaps it took four titles of step-changes to realise the game’s potential. Broad improvements made up for a lack of innovation, with a renewed focus on stealth exemplified in a notoriety system that punished misdemeanours in one level with more wary AI in the next. Improvised weaponry became an important consideration for the first time, and everything from high heels to hedge trimmers were given murderous intent by a re-energised 47. As proof, look up the popular fan-made video that capture the riotous absurdity of a glamorous wife being set alight by a sabotaged barbeque as her protection detail looks on, applauding.

The story of Blood Money proved a more interwoven and personal plot than ever before. It revealed the unlikely spectre of two albino assassins being dispatched to destroy The Agency, in a story that saw 47 not only picking off the usual array of targets – gangsters, politicians, marauding chickens – but evading the target on his own back. The plot arrived on the back of beautifully constructed designs, from the veritable Opera-house sandpit of ‘Curtains Down’, to ‘Murder of Crows’ that set Mardi Gras celebrations as the backdrop for a frenzied massacre amongst the series’ first crowd scenes.

Without cause to repeat themselves even once, IO Interactive brought the story of Hitman to a close in faultless style. First came ‘Dance With The Devil’, a multi-tiered masked ball that saw 47 confront his would-be pursuers in a masked Torture Room shootout plucked from a Stanley Kubrick wet dream. Then came a covert trip to the White House, the controversial setting of ‘Amendment XXV’: a slice of typically misguided controversy that stands apart from its baiting compatriots by remaining fun and considered along with it. It remains an enticing challenge that rewards consideration and experimentation, leaving Amendment as a deserved final intoxication, in which you stride with purpose in a dress uniform to drop the Vice President and completing your guilty ‘Office and an Gentleman’ fantasy.

It can’t be overstated just how effective Blood Money was at simply being Hitman. It traded the innovation of Codename 47 for absolute polish, and replaced the frustrations of its sequels with focus and an AI only as smart as you’d want. It stands as the most consistent, replayable title of the series, varied and absurd. Where else can you tamper with glazed donuts, play creepy peek a-boo voyeur, or shoot unsuspecting guards with tranquilisers from a neighbour’s treehouse? And that’s just one mission. The others were a litany of faked deaths, playboy parties, homages to Luc Besson’s Leon, JR Dallas hats, steamboats, and a giant yellow bird costume for your ever-stoic bald avatar.

Ending with an interactive credit sequence that sees a presumed-dead 47 bound to life with dual berettas for a final, slow-motion showdown, Blood Money was Hitman at its most bold, remaining as ridiculous a conceit as it was a furiously, unapologetically enjoyable one.

So where to now? The fifth game in the series, Hitman: Absolution, remains shrouded in mystery prior to its unveiling at this year’s E3, but one thing is clear: Hitman has to change. The game has been thoroughly explored in three sequels. It’s been done well, it’s been done badly, and finally it’s been done perfectly. The mechanics of assassination that served the series so well for over a decade are showing their age, and its once innovative particulars have been copied and expanded upon by wildly successful rivals such as Splinter Cell – a title, incidentally, that last year underwent its own critical reinvention in the face of diminishing returns.

Whether or not Absolution will challenge its fans with a new paradigm is unclear; early indications suggest it just might. Until then, indulge me in considering an improved Hitman. One that places greater emphasis on a dynamic environment, where the behaviour of patrolling guards can’t be set to a metronome. One that continues to explore environmental kills, bolstered by a combat system that feels a little less like two oafs clumsily falling into one another. Have 47′s targets change their plans, rushing towards the exit as your collapsing objectives force you to improvise. Implement branching conversations that would not only imbued the character with personality, but influence his chances of being detected. Recognise that 47′s stilted movements belong to a different time, and are in desperate need of unshackling in the manner of Ezio Auditore or Sam Fisher. Above all else, bring the world of Hitman to life with character and voice and style. Four games have well and truly proven the formula – now is the time to try something new.

Hitman: Absolution arrives 2012.