My critique style is to include any recurring thoughts as well as any criticism or applause. These extraneous considerations can safely be ignored, or they can be incorporated if the author deems them important or interesting. Of course, the criticism should also be taken with a grain of salt, since I'm writing as someone with only a few months of IF authoring experience.
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>Giving Your NPC a Life of His Own<br>
><br>
>Pick up any novel and chances are good that it will center around a <br>
>character or group of characters, their activities, and what they do.<br>
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The last two items in this sentence sound like the same thing to me. Perhaps for the last item, the author meant something more like "the results of what they do" or "the consequences of their actions." Or maybe they meant something else that I'm not getting.
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I enjoyed the brief discussion that followed about characters in classical novels. This flowed very naturally to a discussion of NPCs in early IF. The following section is particular well said and might succeed in motivating IF writers to put more effort into their important NPCs.
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>Thus, if an author has created a simple NPC who only reacts to a <br>
>single "correct" solution, that NPC will stand in the same place for <br>
>hundreds of moves while the player attempts to discover the key that <br>
>will advance the game. The NPC in this case is little more than a <br>
>locked door, infinitely patient and equally lifeless, and ultimately, <br>
>not very interesting.<br>
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Similarly, the following is a good way to express the ultimate goal of writing a complex NPC.<br>
>The NPC follows the script the programmer/author has written, and<br>
>we, the players, forget  we're reading words on a computer screen<br>
>and become entranced.<br>
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If the player forgets they are dealing with a prewritten script or program, the goal has been achieved. This gives an author a measuring stick for success regardless of their technique.
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>When Should an NPC Have a Script?
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I'm not convinced this is the best title for this section. The first paragraph does answer the question, but then the bulk of the section goes on to cover how the author should handle an NPC who clearly deserves to be scripted. This latter information also bears great similarity to the included sidebar. Perhaps this section could be titled or ordered differently.
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Similarly, the pragraph below might be better off in the section 'Scripting a Life' that follows. It would seem to be a necessary prerequisite for the advice in the rest of that section.
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>Write out a description of a typical "day in the life" of your NPC. <br>
>Our shopkeeper's day might include arriving at work in the morning, <br>
>putting out his wares, cleaning, leaving for lunch, receiving new <br>
>stock, making ice cream, discussing politics with the people in the <br>
>store, managing money at the end of the day, and going home for the <br>
>evening. Whether any or all of this is interesting or important to the <br>
>game will affect how much of it is included.<br>
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>Scripting a Life
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The code examples in this section and throughout the remainder of the article are very clear and concise, in my opinion. I couldn't find a single example where I needed clarification on the code, even after reading through it twice to make sure.
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However, I'm a little confused when the author refers to "returning control to the daemon." Isn't the daemon in control of the subroutine already? Or can the subroutine rest control away from the daemon indefinitely? It's quite possible this makes perfect sense to a more seasoned coder. As a newbie, I don't quite get the language.
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Here are a couple of instances: 
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>In the first thirty minutes of gameplay, Merle does nothing...
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>For this example, nothing  happens, so the subroutine returns
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>control to the daemon.
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And later on, at the very end of this section:
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>If the player is not in a position to see what Merle is doing, we <br>
>simply return control to the daemon routine and don't print anything at <br>
>all.
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>NPCs with Something Special to Say
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This section is so clearly written that I have nothing special to add, other than that it strikes me as a nifty idea that would be easy to implement by an author who is a little intimidated by the idea of setting up a whole daily routine for their NPC.
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>NPCs Who Listen
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Again, the explanation and code given is very clear. However, it might be nice to also discuss what happens when NPCs don't listen. I suspect the messages given for Ask, Tell, Give, Show, etc should indicate that the NPC goes back to their usual routine almost immediately.
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A listening Merle's response to a question might be "Merle considers the question a moment, then answers in the affirmative." And that might be followed by "Merle waits patiently." A non-listening Merle might instead respond, "Merle turns his attention to you just long enough to answer in the affirmative." This might be followed by a description at the end of the turn of Merle's continued actions, which were not significantly interrupted by the player's interaction.
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That's obviously an optional diversion from the main topic at hand, though.
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>The NPC Lives!
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This section brings the article full circle, reminding the reader of the earliest two sections. It's a satisfying conclusion. I find myself considering how, in one difference between novels and IF, the IF player can decide how well they will 'get to know' an NPC. The novel reader only learns as much about each character as the author has determined they will. As a result, I believe the IF player who takes the time to interact may develop a stronger personal bond with the NPC. Not only do they know a lot about the NPC, but it's an achievement they can be proud of.
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> The methods here can be improved upon and made much more complex.
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This might be an understatement. I'm already wondering what happens if the player diverts Merle's attention by interacting with him during the period of time during which Merle would normally leave home and open the store. Does Merle suddenly pop out of existence in front of his house with no newpaper in hand, then pop in at his store with a newspaper? Or will a clever author tag certain sections of Merle's timeline as optional if he's behind schedule? (For instance, Merle opens the store as usual but skips making ice cream that day.) Hmm.
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>Sidebar<br>
>Questions to Ask an NPC
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The sidebar's title is an excellent reminder that the character needs to take on a life of his/her own before the coding process begins. A useful addition for less experienced writers.
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Overall, I think this is a pretty useful article. I'm going to implement some of these concepts in a game I'm currently working on. Though I'll probably have to research a little bit about the exact code needed for the design system I'm using (Inform), I'm sure it won't be too hard. The important thing is to understand how it works on a practical level, which I feel confident about.