Solid strategy experience missing a little something to tilt
To start with, it does have an "age" feel to it with buildings & discoveries needed before you can progress to the next age (up to IV). And units of the advanced ages are more powerful than those of the earlier ages. So you will be battling as one of the five middle-age heroes and there is a reference to history in the 5 single player campaigns (Whether Jeanne d'Arc, Japan or others).
Game mechanics will lead you to discover its rock-and-scissors aspects (with lancers countering cavalry countering swordmen, in turn countering lancers. :-) As usual on the GBA, here we also have an animation showing combat when it happens - which you will probably turn off soon due to its duration.
You will find difficulty ramping up well - up to "rather more difficult than other games" (without reaching the hard mode level of Fire Emblem, as far as I have experienced ;).
Graphically, the game looks good without being excellent. Somehow the theme did not really buy me, even though I did not find anything wrong or lacking with it.
Sound-wise this game has a good rendering. Units mumble something when you select them (there is one speech I still don't understand), weapons sound metallic when they clash, and there is a quite good theme playing in background. However these sounds are not much varied and you likely won't find yourself carried through by the theme as you could with Fire Emblem or Advanced Wars.
Controls are responsive. (Players used to Advanced wars will have to exchange L for R but that's about it. ;) Navigation through maps is a problem though because it feels slow when you want to travel through the map (and there is no shortcut to accelerate this).
You can use the stylus - yes you can. But the experience will leave you willing more reliability. When you select fixed elements of the screen or menus, it works fine. But when you try to select units, due to their overlapping between them and with the scenery, it is unsatisfactory.
There is a bonus points system that will let you buy extra maps and extra unit types.
Overall, I had a better tilt with the other many games from either GBA or DS library - especially Advanced Wars: Dual Strike, Fire Emblem (all 3 games), RebelStar, Zone of the Enders. Because these have a further feel to them - either because they have a story with characters you carry from one mission to the other, or simply because they have a great theme with a flawless execution.
But if you are out of strategy games in portable format - I would say "why not?" try this game.
Note: I have not tried the multiplayer (my personal belief is that it does not really make much fun for a turn-based game to play with someone else waiting for your turn to end.)