This place is dead, so I thought I'd post something and maybe you would like to respond to it. I dunno.
From what I've read, this is not only the best fanfic dealing with the first game in the series, it's one of the best stories dealing with Kyle Katarn. It adds alot to the original game but doesn't really alter any events since they were so few. It adds alot more to the characters too which is the most important part of a story.
Sadly, I hate reading stuff that long on a computer screen so I didn't get too far. It's worth a look though if you're a Katarn enthusiast and like reading.