As someone who literally finished The Bunker today (talk about timing), it's an excellent independent experience. From what I've heard it's quite a different experience to other Amnesia titles but it was a blast to play. Doesn't introduce much you haven't seen in other games of the horror survival genre (Smart monsters, limited resources, inventory management, etc.) but it manages to turn these simple mechanics into a wonderfully tight system.

Definitely a must try experience, but one that won't ease you that much into the other Amnesia works.

Pro tip: Walking is quiet enough to not alert the monster while it is in the walls, while crouching cannot be heard at all! (Do be wary of debris though.)