This is a walkthrough, though you should already know that based on this post's title.
Why am I speaking in italics? It is because I am the Editor and not the Writer, and I speak in italics. (I am still staying in character.)
For the first riddle, just look at it. Look at it closely... Do you see anything odd? Also, what does everybody want, yet nobody has it?
For the second riddle, double negatives are improper English, but the tenses of verbs may matter. Look for loopholes in the suspects' responses.
For the third riddle, what is something that does not live yet breathes (without ever inhaling)? This one is more of a logical deduction than anything. Again, the answer does not inhale. I said it twice to stress that point.
For the fourth (and final) riddle, this one was made unnecessarily complex. You should start at the beginning and the end of the riddle simultaneously. "I will spell terror into your soul" and "I am first." Spell is a pretty odd word to use, right? "I came first." Oh, maybe the answer lies in a precious page. "I am first among first." Hmm, is this a hint? "In order to finish the last, you have to look first even among those not first." You will have to look on multiple pages. Plus, if you answered the past three riddles correctly, just guess until you get the correct answer since you would be immediately taken to a new page. If you are still stumped on the riddles, look in the comments section. I have noticed that they quite commonly give away answers either intentionally or unintentionally.
Additionally, this game is a bloody parody on irksome things writers do. Every spelling error, odd phrase, weird occurrence, and grammar error was entirely intentional.