In short, if you buy Conquests, you don't need Play the World but you still need the original Civilization III game.

The Conquests expansion includes nine professionally and lovingly created conquest-themed scenarios. Each scenario is so detailed it could almost be a separate game but, being greedy, I would have liked even more of them.

Far from being simple scenarios, tech trees, units and even the in-game Civilpedia have been changed in each to give more flavour.

The expansion adds a whole new level of replayability as you can battle out scenarios from any side. In the Age of Discovery scenario, the Europeans arrive in the Americas. Play this scenario as one of the Central American Indian cultures (Aztec, Incan or Mayan) and you are in for a rough, tough and lopsided game in which mere survival counts as winning.

Another noteworthy scenario is the Rise of Rome, in which a young city is beginning to make its mark on western civilisation. Two new units, the Heavy Cavalry and the Fire Catapult, make this scenario unique.

Corruption in the Fall of Rome is rampant and barbarians abound. The mighty Roman empire has grown so large and unwieldy that Emperor Constantine has split it in two - into the eastern and western empires.

The manual includes all the information from the first expansion but I wish that more information had been included on each of the Conquest scenarios. The short paragraphs on each do them no justice.

Seven new Conquests civilisations plus the eight from the Play the World expansion means there are now 31 civilisations with which to rule the world.

The new civilisations are the Byzantines, the Dutch, the Sumerians, the Incans, the Portuguese, the Hittites and, my favourite, the Mayans.

The Mayan Javelin Thrower is capable of enslaving enemy units for your own civilisation.

Each civilisation is characterised by traits that accent their strengths. Conquests adds two new traits: seafaring and agricultural.

Civilisations previously part of the game are tweaked to reflect the new traits. So, for example, England is now seafaring/commercial instead of expansionist/commercial.

Two new difficulty modes - demigod and the even more difficult Sid mode (named after the creator of the game, Sid Meier) will challenge even the most experienced players.

Seven cool new units are available to all civilisations. One is the Great Scientific Leader. Be the first in the game to develop a new technology and there is a chance that a Great Scientific Leader will join your civilisation.

Great news for multiplayer fans is that the mode has been improved for faster game play, with simpler combat animations and faster resolution of stack combat.

Civilization III's artificial intelligence is much more advanced than its predecessors', and smart enough to hit you where you are weak. This rarely happened in previous games of Civilization.

I offer my bloodshot eyes as proof that Civilization III: Conquests is horribly addictive. It extends and expands on the greatness of Civilization III and is a magnificent addition to any gamer's collection.

No other computer game screams out the adjective 'replayability' like the Civilization franchise does.