The Desert, 925 BC. A religion is born on a desolate strip of land connecting two vast continents. A great prophet appears in the capital with news that the divine baiting Word of the Trolololomites is primed and ready to be spread to the far reaches of the earth.

It’s all thanks to Civilization V: Gods & Kings’ new resource: Faith. After earlier selecting Desert Folklore as a Pantheon (+1 Faith for all desert tiles), this divine currency has been slowly accumulating due to additional Shrines built across the land. When a certain threshold is met, a Great Prophet is sent to establish a fully-fledged religion that can be modelled on any of the existing world religions, from Christianity to Zoroastrianism, or customised entirely to the player’s preference.

Firaxis’ first expansion pack to Civilization V is best viewed as a requisite corrective measure. New units, wonders and civilisations with inspired unique abilities such as Carthage’s mountain crossing, and Ethiopia’s bonus against more established rivals are great, but they’re merely the cherry on top. The re-introduction of espionage and religion to Civilization is a return to form for a series that seems to have struggled somewhat with its identity over the past couple of instalments.

Taking things back to the gospel, religion is built on beliefs, and the selection of Founder and Follower beliefs available allow the player to customise a chosen creed to his or her needs. Founder beliefs directly aid the player, whereas the benefits of the latter are extended to any foreign city where the catechism has taken hold. For example, Tithe delivers +1 gold per follower. It may not sound like much, but a focus on missionary work early on can pay dividends in the late game.

On the other hand, Papal Primacy provides an influence gain with city-states that follow or lean toward player’s religion. Whether the player is gunning for a military victory, or aspiring to lead the world in scientific thought, the wide range of beliefs mean differing play-styles are well catered to. When it comes to evangelising, great prophets and Missionary units go out into the world to spread religion, while Inquisitors hang around contested cities to stamp out the heresies of other faiths.

Combat on land and sea has also been dramatically overhauled. AI is improved and unit health is now measured on a 100-point scale. Battles last longer as a result, meaning there’s time to tag in fresh units around those that are on their last legs. Together these adjustments provide a much-needed tactical boost to the established scope of combat in Civilization V.

On the high seas, embarked units are now able to defend themselves, and warships fall into two categories - ranged and melee. Melee vessels, such as Triremes and Destroyers, have the ability to board or ram enemy vessels, and can lay siege to coastal cities, forcing fleets to think defensively as well. The inclusion of Great Admirals means fleets can be instantly healed at sea, rather than having to sail back to port.

Concerning sieges themselves, siege units have been given a formidable attack bonus against cities, while the hit points and defensive capabilities of cities have been considerably enhanced to provide a greater challenge. Additionally, any unit within a city is now automatically considered a garrison force.

Moving forward to the Renaissance, the theatrics of religion take a slight backseat to the return of espionage. Spies don’t have a physical presence on the map, they’re given orders through a side-menu, but they work much the same way as they do in similar titles.

Rather than being trained, they’re allocated as the player advances through eras, and their experience is gained via assignments such as stealing technology or election rigging to curry favour with city states. Of course nothing is a sure bet, and a delicate job gone wrong can quickly sour poor relations into open warfare. Each assignment carries a certain amount of risk, so the more seasoned they are, the higher the odds of success.

The understated espionage menu might not have the same presence as religion in Gods & Kings, but it is a further layer of complexity in terms of defining the way civilisations can interact with each other. Just as the spread of religion can earn rewards in the form of attack bonuses or gold, stolen technology gains and politically motivated coups can bolster late-game progress.

Three new scenarios also provide an interesting distraction. Set in the empire’s twilight years, Fall of Rome casts the player as either chief of the barbarian hordes, the covetous Sassanid Empire or the fragments of Eastern and Western Rome. The stakes are historically heightened for the Roman factions by social policies that are better described as penalties, such as Usurper General and Dark Ages that have the effect of inciting revolts, steadily raising costs and reducing happiness.

Into the Renaissance deals with a similar foreign threats in the form of the Mongols and Ottomans, and new agitators such as the Almohads, but with three holy cities and the title of Holy Roman Empire up for grabs the religious focus is clearly played up.

However of all the scenarios, Empires of the Smoky Skies has to be the most novel experience. Four suitably steampunk civilisations share a set of new technology inspired by the Industrial Revolution. Victory comes from leading the field in three of five honourable titles concerning military, commercial, industrial prowess, and so on. The sight of armed zeppelins battling it out in the skies whilst tracked, heavily armoured environmental nightmares tread the earth below ought to be a heart-warming sight for even the most traditional of Civ players.

The litmus test of any expansion pack remains its perceived bang for buck. Regardless of how enthralled or disgruntled fans were with Civilization V, Gods & Kings represents another shattering blow to even the most casual gamer’s potential productivity. It’s a welcome, if not a little overdue redefining of what the base game should have been.

Religion and espionage alone do not a revolutionary gameplay experience make, but combined with the strategic combat overhaul and a generous helping of new content, it all adds up to far too much time spent playing into the wee small hours.