Operation: Anchorage involves the Outcasts, the group of soldiers who splintered off from the Brotherhood of Steel due to philosophical differences. At some point while you're exploring the wasteland, you'll receive a distress call from the Outcasts, and when you fight your way to them, you'll find them in a military installation. They'll explain that the installation contains an armory with lots of high-tech goodies inside, but that the only way to get into it is to beat a VR simulation about the liberation of Anchorage, Alaska from the Chinese. The reason you have to help is because the simulation requires a computer interface that just happens to match your Pip-Boy 3000.
The set-up is decent enough, if a little unlikely. It was nice to see the Outcasts get into the spotlight, since they got so little play in the main campaign, and fighting Chinese soldiers in the mountains of Alaska is also nice, just because it's so different from everything else in the game. But the problem, or perhaps I should say one of the problems, is that Bethesda created the content so it could be completed by almost any character (you can actually trigger the quest at level 2, immediately after leaving Vault 101), and that means everything about it is easy for advanced characters.
Let me give you some examples. You start the VR simulation with a knife and a 10mm pistol, which aren't exactly the most powerful weapons in the game. But you can complete the entire simulation with just those two weapons if you want, and not have too many troubles. If you actually use the assault rifle or the sniper rifle or the new gauss rifle that you can find, then the Chinese soldiers will go down like weeds versus a weed whacker. Or how about this? Bethesda actually took out the need to scrounge for bullets, or to collect stimpaks, or to keep your equipment repaired. Instead, you find (health dispensers) and (ammo dispensers,) and the dispensers are so liberally placed that you can spray bullets around all you want, and you don't have to bother with sneaking or using cover at all. If you like playing action games in god mode, then this is about as close as you can get without having to use a console cheat.
One nice thing Bethesda did in the DLC was to hide some (intel cases) inside the simulation. If you manage to find all ten of them, then you'll gain a perk that will increase your lockpick, science and small guns skills. It was sort of fun to hunt for the cases and to wonder what the reward for them might be, but even here there are some problems. For example, everything that you can interact with in the simulation (including the cases and the dispensers) pulses red. Since the color palette for Alaska tends to the white and gray side of the spectrum, that means everything you can use is pretty easy to spot, and so it's not exactly a challenge to find the intel cases. Also, most of the cases are hidden in locked storage rooms with (easy) or (very easy) locks, which is just another example of how unchallenging the new content is.
Also disappointing about the DLC is how linear it is. Bethesda must have been playing a lot of Dungeon Siege prior to creating Operation: Anchorage, because there's basically a straight line from the beginning to the end (the only decisions you get to make are of the (should I got left first or right first?) variety), and your companions, such as they are, don't add a whole lot -- and that's even if you can tell what they're saying, which I couldn't most of the time.
Operation: Anchorage adds four new quests that will take you about five hours to complete. There are also some new items that you can find, such as the gauss rifle, which is the energy weapon equivalent of the sniper rifle, and some of these items can even be taken with you after completing the simulation (thanks to the armory that the Outcasts are guarding). But otherwise there's little to recommend about the DLC. It's linear and it's easy and it adds almost nothing to the Fallout 3 universe. To me it sort of felt like a quarter of an expansion pack at half the cost, which isn't a good thing.