Strategy Lite, but still not bad on its own merits
Halo Wars is a great game, and a fantastic addition to the Halo Universe, but if you do not have Xbox Live, its appeal is limited.
The campaign is very good. It provides a variety of missions, and a very good storyline supported by great cutscenes. It does not do a great job of sucking you into the story, but for an RTS game, it is better than adequate. The campaign is short, but it is supported by the addition of skulls to find and very difficult upper difficulties.
For single-player only players, there is also quite a robust skirmish mode, from 1v1 to 3v3 against anywhere from the ridiculously easy, Easy level, to the ridiculous Legendary difficulty, plus skulls to change things up, it is very good. However, because this is an RTS, there is no split-screen.
This means that if you want multiplayer, you're going to need Xbox Live. This is where the true meat of the game is. The entire campaign is playable in co-op on Live, but it is not the greatest way of doing it. All funds are shared but troops aren't, which means that while communication is important, it can get frustrating if you're waiting for an upgrade and you're friend builds 5 warthogs.
There are also competitive modes, deathmatch and skirmish. Deathmatch gives you full techs and tons of resources and is a fight to the death. Skirmish gives you few resources and no techs, and you'll have to build your way up. The leader that you pick and your choice of units and tactics are essential in skirmish. And playing 2v2 and 3v3 really requires communication and tactics. This is where the true meat of the game is, and if you have XBL, its absolutely fantastic.
The control scheme works quite well, as long as you don't micromanage. It is incredibly difficult to use the special attack (which most units have and is quite cool) of several of the same units on different enemy units. It is very easy to select large groups of units, and the individual unit types out of that, but anything beyond that is difficult.
Overall, Halo Wars is fantastic, if you take it for what it is, a console RTS. The campaign is quite good, with good variety of missions but it's quite short. The skirmish and online are where the real meat of the game is, and it's fantastic with buddies or even alone.
Note: This review is on multiple sites, all my own personal usernames.