"In this game you play Shelby, a young apprentice to the 'Regulators', Holcroft and Barclay. You live in a remote lighthouse where you nominally study physics, but actually spend most of your time cooking and scrubbing floors. Returning to the lighthouse after an extended period of absence, you find that things have gone wrong. An ominous mist surrounds the lighthouse and Holcroft and Barclay are nowhere to be found. It is up to you to find out what is the matter, and to put things right again.

Most of the fun in this game is figuring out the background to the world McCarthy has created here, so I won't reveal too much about it. Suffice to say that this is a world somewhat like ours, but in which 'physics' is a very different subject from the physics we know. The how and why of this world is revealed tantalisingly slowly, a little in the room descriptions, some more in books, magazines and other papers that you read, and some more that you have to guess for yourself. The idea of alternate worlds, and the uses to which they might be put (if technology were to allow their manipulation), play a strong part in the rationale for the plot and some of the game mechanics.

Although the discovery of the background is interesting, the actual mechanics of the game are disappointing. Some of the text is good, notably the introductory paragraphs, but much of the rest is rather lacklustre. Room descriptions have a tendency towards lists of furniture and exits, and there are rather too many rooms in which nothing happens (I counted 25 that could have been removed without loss). Far too many of the puzzles require you to read through the room description, examine every object mentioned and look under every piece of furniture. Several locations seem to be full of clutter for the express purpose of distracting you from the one object you need to investigate.

Some of the puzzles seemed completely arbitrary to me, and even after solving them I still don't understand why the solution worked. For example, there's a puzzle with two circles on the ground; if you put the right objects in the circles, a secret door opens. As far as I can tell, there are no clues to which objects to use. Another puzzle uses an oxygen cylinder and a pump to make a submarine appear; I might have understood this if the submarine had been in an underground chamber full of water that needed to be pumped out, but in fact the submarine appeared in the open sea. So what was the oxygen used for?

...I've been rather harsh in this review; there are good aspects to The Light: Shelby's Addendum, and it would not have been out of place had it appeared as a mid-period Infocom game. But I didn't enjoy playing it very much because the moments of excitement were few and far between."

Recommended on the strength of the writing, but be warned about the more than usual dose of unfair and frustrating puzzles in the game. Keep a walkthrough in hand!