A Z-Code game written by Michael S. Gentry and released in 1998.
A self-designated genre-piece, Anchorhead is written in the mode of Lovecraftian horror. Set in Achorhead, a small New England town (near the equally fictional Arkham), the game casts you as the nameless wife of Michael (quite clearly the author himself) who inherited a mansion from a distant relative he never heard of. The mystery begins when the real estate agent, who was supposed to deliver the keys to you when you arrive, fails to show up.
The first puzzle consists of you breaking into the agent's office, and it sets the pace for most of the game: sensible puzzles that are logical, enjoyable and seamlessly deliver plot.
The best facet of the game is its writing (though the coding is superb as well. I have found no problems with the second version) - Gentry does Lovecraft better than Lovercraft ever did. Descriptions are never over-the-top but always convey a sense of lurking horror, as if, could you turn your head fast enough, you would see terrible Old Ones hiding behind the fridge, their damp tentacles grabbing for mouldy piece of pizza.
It is obvious that user friendliness was a big issue for the author. For example, the game features one of the best inventory systems I have ever seen - the player can hold only two items at any time, but they always wear a trenchcoat which is used not only for easy storage, with its seemingly infinetly big pockets, but automatically manages the pockets as well, so the player never has to manually type commands to free his hands. Another example would be the keyring which serves as a centralized center of key-keeping (imagine that) and will save you the headaches involved in remembering which key opens what.
Anyway, this was the first serious piece of IF I played and finished, and I enjoyed it greatly. Anchorhead is responsible for my current love for this great genre. So go download it at some place like Baf's Guide to the Interactive Fiction Archive(http://www.wurb.com/if).