Summary: I'm not sure why this is $5 cheaper here than on the Steam store, but it is, which is pretty cool. The DLC itself is a single-player story campaign that can take anywhere from 2 to 6 hours depending on how much you explore. If you do like to explore, then I can't recommend this game highly enough for people who have BioShock 2. The environmental storytelling is excellent, and there's plenty of rewards to be found by veering off the beaten path.
Summary: I'm a big fan of the Bioshock series. Minerva's Den is a nice addition. It had a balanced mix of a new playable area and additional features that include new tonics and powers. One thing I am a bit sad about, however, is that this content isn't added directly into the game. You play it separately like a side game vs an actual add-on. Another fun set is the Protector Trials.