A full package of more the same.
Around 90% of Earth's population has been killed in meteor strikes, which caused a massive dust cloud to form and blot out the sun. In this situation isolated military troops are either trying to preserve order and protect the people or try to take advantage of the situation and rob everything valuable. A young cadet from the Rubinelle military academy named Will escapes the ruins and is confronted by The Beast, a former sergeant gone rogue who leads a small band of raiders. Will is rescued by Brenner and Lin of Rubinelle's 12th Battalion and takes on the group's cause of saving as many survivors as possible. After a while Will discovers Isabella, a mysterious amnesiac girl, who somehow knows detailed military information. Eventually she becomes a vital part of the 12th battalion as they put an end to the Beast's reign of terror. Story is told entirely in still images and text boxes and there's a lot of it. Luckily the script is well written and the story flows nicely forward.
Graphics are not the best DS has to offer. Everything is quite blocky and there's nothing that couldn't have been done in Game Boy Advance. Battle animations especially are horrible, but you can turn them off from the Options menu. Darker story reflects to the graphics in a way that pretty much everything has a shade of grey in it. Music and sound are well done, but they tend to loop way too often and after a few hours you'll be just fine by playing with all the sounds turned off. Luckily the game let's you do just that and there are plenty of different options to fine tune the gameplay as you see fit.
Controls are easy to learn and they are also taught very clearly. You can use the touch screen to make decisions, but it's still easier to use d-pad and buttons. Upper screen provides information about a selected terrain, building or unit.
Actual gameplay is classical turn-based strategy and the campaign offers 26 different missions. Aside from that there are 38 optional missions, which are quite challenging and really force you to think. Every unit has strengths and weaknesses which you need to know and use accordingly in combat. Proper use of terrain is essential to succeed and you'll learn it quite quickly.
Save system works great: you can save anywhere and anytime. One mission can take from 30 minutes to an hour to complete so for this reason there's a special Tactics option and this means that the game gives you hints on how to proceed. As a whole the balance of Days of Ruin is done right: first few missions are easy and in them you'll learn to use your units and terrain, but later it comes much more challenging.
When you're done with the campaign and those optional missions there's also Free Battle mode, in which you complete a series of tough missions. They don't have anything to do with game's story, but it adds a lot more gameplay to this package. Also everything you do is tracked in Records menu and it's always encouraging to see how you make progress.
Days of Ruin also includes multiplayer mode, either via multi-card wireless play or through a Wi-Fi connection. Here you can battle against other human opponents and it's usually much more challenging than playing against an AI. It also means that one battle can literally last for hours so I expect that you don't do online matches that much when comparing to single player challenges.
Finally there's the Design Room in which you can make your own maps and share them with your friends either locally or through a Wi-Fi connection. This is again one more component to make you come back for more Advance Wars gameplay.
Advance Wars: Days of Ruin is a full package of features and gameplay that you might want from a turn-based strategy game. It doesn't bring anything new to the table when compared to previous games in the franchise, but it's still a polished and solid title. If you're new to this series there's no better time than now to take a look.