XCOM: Enemy Unknown - seven essential tips you'll need to save the Earth

As you'll know if you've read our XCOM: Enemy Unknown review, the latest Xbox 360 release from Firaxis makes being hard an art. It's a game about juggling resources, struggling to get by, being forced to make life-or-death decisions.

We'd highly recommend playing on the Classic difficulty setting - Normal is a little too forgiving - but you might want to pick up a few pointers first. The early stages of the invasion won't pull any punches. Start reading ahead if you want to survive.

Rookies aren't much use in the field, and have a habit of dying. Soldiers are cheap enough to replace, but don't get into the habit of shrugging death off - success in the later stages of XCOM is dependent on the quality of your troops, which means keeping them alive for long enough to earn those promotions.

Taking a full squad of rookies into the field is suicide, but it's worth bringing someone fresh along with you on every mission. Aside from the Assault's invaluable Run & Gun skill, most of the classes take a while to get good. Snipers are rubbish for the first few ranks, but eventually develop utterly invaluable skills. Read our XCOM: Enemy Unknown class guide for more pointers.

Rely too heavily on your XCOM A-Team, and you'll soon find yourself in a sticky situation. If a Terror Mission pops up while the heroes of your squad are still in the infirmary, prepare to sacrifice a couple of rookies at least. The officer training facility can be handy: it lets you buy upgrades that increase your squad size to six, which makes spreading out the promotions much easier.

You won't have been playing XCOM for long before the research team starts bugging you to make an Arc Thrower. Get close enough to an alien whose health is low, and you'll be able to zap the cheeky git unconscious and haul it back to base. Interrogating a species unlocks research credits, speeding up the rate at which you unlock certain specific technologies.

Because of this you'll want to capture aliens as soon as possible, but doing so always puts you at risk. It's best to give your Arc Thrower to a Support class soldier - the extended movement range perk makes things much easier, as does the upgrade which adds a secondary inventory slot. If you can't quite make it to your foe in one movement, find some good cover and use the Hunker Down skill. This ability gives you full protection against critical hits, which should help you survive any last-ditch resistance.

Get into the practice of capturing live foes, and you won't have to invest as much money on your research team, allowing you to spend cash on engineering.

It's easy to get carried away with building research labs, but it's worth making a few workshops as early as you can. Placing them adjacent to each other in your base gives you a 7% spending rebate per workshop. In addition, the engineers that come with it will reduce the cost of making new stuff.

Later in the game you'll find the costs of building weapons and armour a little more hefty than you might expect. Invest in engineering early and you'll save a fortune in the long run.

You'll also be quids-in when it comes to meeting requests for equipment. If some chaps from Russia want to buy some laser rifles, get down to engineering and build them immediately. Using up rare materials in the process might not be wise if you're running low, but when stockpiles are at bursting point, this is a bit of a no-brainer.