Great strategy and some history mixed in makes this a surprisingly good game.
-.5 for graphics
-1 for the occasional glitch, very annoying in 2 player when the game freezes up, but bearable in 1 player. (don't let this scare you, these are rare, just really annoying)
Difficulty and time spent:
Very hard in the advanced stories, even the later levels of the dubbed "easy" story, and the free play can be as punishing as you like. I still haven't beaten every story, so I promise you'll get your money's worth of play time.
Gameplay
Play as one of five civilizations in medieval times, create over 40 different unit types, over 15 different buildings, on over 20 battle fields. Turn based strategy gameplay is spiced up by scenes of armies clashing on the top screen whenever an attack is made. The key to victory is a combination of a mighty army and a good economy which can be achieved by building mills, mines, and researching new technologies. The gameplay is deep, and a single war can take over 4 hours to complete, depending on the circumstances.
Summary
One of the best turn based strategy games for DS out there, well worth the money at a $20 price tag. A tad challenging and time consuming, so I don't recommend this for anyone that isn't a hardcore gamer.