Tactics and formations are individual policy cards that give you specific advantages when in battle. Formations upgrade your attack, defense, or speed abilities, and there are varying degrees of effectiveness for each. If you use a first-tier speed-based formation but your opponent is using a second-tier attack-based formation, the effects of your formation will immediately wear off, and you'll be at a disadvantage. Tactics are much more specific. Some let you hire ninjas to accompany you in battle, while others lower the movement speed or morale of enemy soldiers. There's lots of variety to these tactics, and there are many instances where they can be the difference between victory and defeat.
Messing around with all these various policies and shuffling around your officers and their troops to create the most beneficial battle scenarios possible is pretty much what makes empires mode any fun at all. The game is effectively hamstrung by the crushingly dull combat, but the strategy of the mode adds a bit of context to the mindless battles, which makes them tolerable. There's not a whole lot to the game beyond the empires mode, unfortunately. There's a free mode where you can just pick a battle and a warrior and have at it free of any context, as well as a create-an-officer mode that is exactly what it sounds like. You and a friend can play in any battle cooperatively, though it's only split-screen play and there's no competitive multiplayer to be had. Granted, it's not like the combat system would make for particularly engaging multiplayer battles, but it's disappointing all the same. Lastly, if you go with the 360 version of the game, there are 17 achievements to be earned. They're almost exclusively easy to earn if you just play through the normal course of the game.
What's perhaps most disappointing about Empires is that the series hasn't evolved into a full-fledged Xbox 360 game yet. This is still a cheaply made port of the PlayStation 2 game, complete with all the awful environmental textures, recycled bad guys, and cheap-looking animations. In HD resolution, the main warriors and officers look a bit snazzier, but that's really the extent of it. As for the PS2 game, it looks altogether the same as every other Warriors game has for the last couple of years, with the same occasional frame-rate troubles and all.
On its own merits, Samurai Warriors 2: Empires is yet another better-than-the-original-version update, simply because of the engaging strategy elements. But it's not enough this time around to make it a qualifiedly good game, and it's never going to be again until Koei snaps the series out of its current rut.