Civilization IV: Defenders of the Gates

One point we should get out of the way right now is that this game isn't Civilization. In name it is, sure, but if you're looking for a mobile re-creation of one of the most iconic gaming experiences ever, you'll have to seek out the N-gage version of the original Civilization, or perhaps the Civilization-apeing Revival Deluxe.

There's no city building here, no trade route pioneering and no trireme-based sailing of the seas. Instead, Civilization IV: Defenders of the Gates is a tower defence game that utilises a few recogniseable elements from the original to give proceedings a Sid Meier tang.

For those unfamiliar with this relatively young genre, tower defence games involve placing towers and other weapons along a path in order to do away with wave after wave of invading enemies, in this case the barbaric 'Huns'.

The key to a successful strategy is managing where exactly to place your defenses and in choosing which towers to upgrade and when.

The Civilization seasoning is applied in three ways. Firstly, you get to choose one of four nations to play as before you start proper. Each has a partcular advantage, whether it's extra population (extra lives in effect), additional gold, a higher interest rate or a technology bonus.

There's also a familiar technology tree from the PC Civilization games. Every few waves, you get to choose a technology to research. Technologies give you important bonuses, from enabling new towers and upgrades to allowing you to buy back population points.

Again, some of these are more important to have than others. If you don't research air turrets pretty sharpish flying units will soon finish you off, for example.

The last PC Civilization feature included is the way that you work your way through the ages of a civilisation as you play, from mediaeval to the modern day.

In gameplay terms, this doesn't mean a great deal, but the enironment changes a bit visually and your enemies evolve from club-wielding barbarians to musket men, and then on to marines and airplanes.

There are 50 waves of enemies to survive, and rather than have sets of different environments to place your turrets on you actually use the same path for the length of the game.

It seems rather long to begin with, considering you'll only be using a handful of towers for the first set of waves, but if you place your towers wisely you'll finish off the enemies long before they reach the end anyway.

Each tower has a certain shooting radius around it, and firing rate and damage amount are the other two main characteristics of any tower. You can also research towers that slow enemies down and ones that do extra damage against particular types of units.

There's a certain amount of money-managing involved too. Killing units earns you cash, and after each wave you gain interest based on the amount of cash in your coffers, so you need to try and spend frugally if you want to be rich enough to afford to buy new population points. Babies are frightfully expensive in the world of Defenders of the Gates.

There are some balance issues - namely that nations and technologies are really quite uneven. In order to make it to wave 50, you'll most likely have to play through a few times in order to find out which technologies to research and when.

There's also not quite as much content here as some other tower defence games. Where Tower Wars offers loads of different levels, here you've just got a different path for each of the game's nations.

However, Civilization IV: Defenders of the Gates is up there with the best games of the genre in terms of that compulsive 'one more wave' gameplay.

You can leave your game at any point and resume it as you wish, but you're likely to find yourself fighting to the death more often than not, right up until you grimace into your handset as that boss enemy slumps past your last super-duper arrow turret with half a sliver of health left.

Civilization IV: Defenders of the Gates is, at first glace, only a Civilization game in the most tenuous of senses. No doubt, there will be many gamers who won't get quite what they're expecting with this title.

Once you've dug into the game though, you'll find a satisfying experience that does incorporate a number of quintessential Civilization features while offering gameplay arguably more suitable for mobile than an attempt at the megalomaniac's world-building classic.