Advance Wars: Days of Ruin/A Single Life

Storyline
Will recovers from his ordeal and is still adjusting to the destruction around him. The atmosphere is filled smoke and ash, blotting out all of the sun's rays. Lin explains that this is caused by ash and dust thrown up into the atmosphere by the meteor strike and could last for years or even decades. Brenner reminds Will to "Never give up!"—a phrase repeated throughout the story.

Will leaves to help search another area for survivors, turning up nothing, when he is attacked by The Beast again. Brenner takes over the battle. During the battle, Will finds a mysterious girl in the ruins of a city who has no memories of her past but does have detailed knowledge of the country and army of Rubinelle. Will rescues the girl and tells her that she could come with them. After the battle, Brenner and Lin are mystified by the girl, her survival and her unusually specific knowledge.

War Room Tactics

 * Artillery has a long range, which makes it very useful. However, it can't attack adjacent enemies.  Block the road with your tank, and pound enemies with the artillery.  Don't allow the tank and the artillery to get separated.

Guide
This is another mini-tutorial battle, with your first taste of indirect-fire units and an explanation of ammo, fuel & terrain advantages.

To start off with, use the tank to attack the infantry unit. Your tank is out of ammo so it can only use its secondary weapon, a machine gun. Since tanks use their machine guns anyway on infantry units, regardless of ammo, it's still very effective. Next, move your artillery in line right behind your tank so that it can fire on both the square in front of the tank, and the square just to the north. Move your infantry unit into the mountains to attack the enemy’s infantry unit, which should be destroyed causing your infantry unit to level up.

On The Beast's turn, your enemy will move his 8 HP recon unit to attack your infantry but your troops will survive. During the start of your next turn, you will need to move your infantry unit to the ruins in the middle of the mountains. A cut scene will take place.

After the cut scene, it’s time to get back to the fight. Fire your artillery at the northern recon unit, destroying it, and use the tank to attack the southern recon unit (the one that’s next to your tank). When the enemy tank moves into range, shell it with your artillery piece (leaving it with 1-2 HP). Move your infantry one space to the left, remaining in the mountain range. Again, use the tank to attack the remaining recon.

Finish off the enemy tank with some machine gun fire from your own tank. Now use your artillery on the motorbike. With the bike unit badly damaged, your nearby infantry should be able to finish the job at the end of Day 4.