These is a very good reason that Civilization IV won so many Game of the Year awards last year - it is a truly great game with something to offer kids and adults alike. The expansion pack, Civilization IV: Warlords, fixes minor issues with the original game while adding a number of new leaders and classes, as well as bringing in new scenarios that allow you to play out different parts of history.

In terms of gameplay, the expansion is identical to the original - all changes are to the content. In the basic civilization-building mode you start at the dawn of history and build up your empire however you choose - you can become a beacon of culture or a terror of brutality. You choose a map and world type, then a civilization, leader and difficulty level and you're on your way. Each leader/civilization has a unique set of personality traits that shape their strengths and weaknesses, a set of starting technologies, a preferred civic and a set of unique units and buildings. Once you have founded your civilization, simply select your units and give orders - build your cities, amass armies, research technology, make and break alliances and trade pacts. Scroll around the map, right-click on things, check the information tabs on everything in sight. The mouse and keyboard interface takes a bit of getting used to - not because it isn't intuitive, but because of the massive scale of the game and the amount of information provided. I recommend going through the tutorial again if you've been away from the original game for more than a few months.

Civilization IV could almost be classed as 'edutainment', based on the sheer depth of historical information available. The expansion further tunes the civilizations and their leaders to make it more appealing to use their natural strengths (e.g. trying to be a philanthropic culture as Ragnar of the Vikings is harder than just wiping everyone out). Of course, having historical elements doesn't imply historical accuracy - you can play as the new leader Shaka of the Zulu nation and found Christianity before building the Great Wall and the Statue of Liberty next to Shanghai! One great thing about the original that made it great for children was the breadth of difficulty levels. Take on 'Settler' level and you can make many terrible mistakes yet end up winning the game eventually. Work your way on up the difficulty levels at your own pace and you are rewarded with greater satisfaction - and punished more and more for every mistake. Just like the original, you need to pay attention to what is going on throughout your territory; you can automate many tasks, but you still need to maintain balances in all of your cities, ensure trade and security, and develop the right technologies and culture in the right areas if you hope to win. The additional cultures and historical scenarios only serve to strengthen the reasons why this is a great game for all ages - you can easily become a history buff with this game, one turn at a time.

There have been a ton of enhancements made to the core game - too many to list in fact, so I'll just highlight the areas that have seen new additions. There are new traits for leaders, such as Charismatic and Imperialistic, which alter how you build your civilization. For example, Charismatic leaders get a happiness bonus in each city, plus an extra bonus if monuments are added, while units require fewer experience points per promotion. Many existing leaders have had changes made to their traits, so matching your strategy to the traits of your chosen leader is critical to success. New civilizations and leaders have been added as well - six new civilizations (including Vikings and the Ottoman Empire among others) and ten new leaders (Egypt, England, Rome and Russia get additional leaders). Each of the new civilizations brings with it special units and characteristics that allow you to better simulate the realistic growth of that civilization... without the downfalls, of course. The new civilizations also come with new unique units, and a couple of additional units were added - the trebuchet siege unit and the trireme naval unit. The final additions to the buildable units are three new Wonders - the Great Wall, Temple of Artemis and University of Sankore. These can be built whenever you are ready and the Great Wall scales with the size of your borders across the area, meaning that it might starts as an 'Average Wall', grow to a 'Pretty Good Wall', then a 'Very Nice Wall' before actually becoming a 'Great Wall'.

The namesake addition is that of the Warlord (also known as Great General) class - when you have amassed enough military experience a warlord is born in a city. You can use them as a Great General to construct a Military Academy or join a city as a Great Military Instructor. Each of these add strategic bonuses that are of great benefit; but the real strength is transforming the Great General into a Warlord - then they can join up with some troops to make a formidable force unlike any other unit on the battlefield. When joined with a Warlord, the units get several upgrades, plus a selection of new bonuses, including Combat (extra strength), Leadership (more experience from battle), Medic (extra healing), Morale (extra movement) and Tactics (better chance to withdraw from battle). Taking these units into battle, you will immediately see what they can bring to your force - but they are not invincible, and once lost are gone forever.

Another large addition is the 'Vassal State' diplomatic option, which allows one nation to be dominant over another in a relationship. Instead of typical treaties, this is described as an asymmetric alliance, as the master has complete freedom and use of the vassal's territory and resources but pays a price because keeping the relationship going causes a burden on the master's resources. I didn't think I would use this option, as I tend to avoid war unless I'm sure I can win, but in one campaign I ended up in large wars on two fronts and my resource production was being heavily taxed. When one leader offered capitulation, I took the offer and had a nice vassal state while I crushed the other civilization... of course, after the vassal treaty finally expired I was able to crush the original state too!

This is an amazing amount of content - well worth the price of the expansion pack. I found that the new intricacies increased the apparent difficulty as well - my first campaign in Warlords playing as Ragnar controlling the Vikings took me far longer than any other campaign I had ever played in the original game. But while all of the core game improvements are welcome and worth the price of the expansion by themselves, the new Scenarios are a great addition that is the best and most interesting part of this package.

Warlords comes with eight scenarios, in which you pick up a civilization already formed at some point in history and need to meet stringent objectives however you can. For example, one of my favourite scenarios is the Peloponnesian Wars; in this module you choose whether to control the already very powerful forces of Athens or Sparta. The goal is to gain domination over Greece within 100 turns. The civilizations of Athens and Sparta each have vassal states and very different traits, so the relative strength and level of development makes this quite a challenge. You need to role-play the leader in order to maximize your effectiveness if you are to have any hope of achieving the goal. Playing each side feels like a different game, and there is enough variety within the constraints that there is tremendous replayability for this module. That is true for all of the other scenarios - Chinese Unification, Alexander's Conquests, Rise of Rome, Vikings, Genghis Khan, Barbarians! and Omen. Each one is unique and challenging, providing masses of opportunity for strategy and replay value. The last one - Omens - is not a truly historical setting, as it involves incurring the favour or wrath of the Christian deity. Nonetheless, it is an intriguing scenario that's a blast to play.

The graphics and sounds remain untouched - and that is a good thing, since Civilization IV is a wonderful game to look at and has excellent audio. The quality of the presentation is outstanding, but the game does have very taxing hardware requirements for the strategy genre. It plays nicely in a window, although I consider that a mixed blessing, since it is hard enough to pull yourself away from game when it's full-screen!

I loved the original Civilization IV - it was one of the smartest and very best games of 2005. Civilization IV: Warlords is a great example of what an expansion should be - fix problems with the original game, add a lot of features that makes the original game more interesting and sends you back to replay it even more, while also adding new and unique content that challenges you in different ways to the original game. Warlords executes all of this beautifully, making it more than an easy recommendation - if you own the original then you should consider this a must have, and if you don't, well, there's never been a better time to get hold of it, along with this new expansion.

Reviewed by Michael Anderson for AceGamez (All Rights Reserved).