The thing I like most about Rules of Engagement is its customizability. In Rules of Engagement you can customize absolutely everything, from ship captains to aliens' races and missions. Also, there are detailed dossiers on a lot of alien races, as well as bios for all of your captains.
The customization isn't just about physical features and biographies, but you can also change the traits of the various aliens. You can make the races stupid and weak, or brilliant trigger-happy death machines, depending entirely on your whim. You can even edit the capabilities of your ships and captains.
Anyway, now for the story. You are a fleet commander for the Federated Worlds Armed Forces (FWAF), and you are at war with the United Democratic Planets (UDP). In your fighting you will encounter various alien races, all of which are hostile. You begin with a very nice title screen, where you have a number of choices. I hope at this point you have downloaded the manual and read at least part of it; otherwise you will be lost. So, you create a commander and choose a mission for him to command. Let's get this started!
The tactical screen is where you administer some searing laser/missile justice. Just remember, if you kill them and you're not supposed to, it's GAME OVER!
Now things get interesting. Look at the briefing and decide on a course of action. You fly one ship while the computer flies the rest, as per your orders. Use communications to give your other vessels their orders, and have some fun! Oh, and don't forget to read the briefing! Overall, due to the game's replayability and customizability, I give it a 4.