I for one like writing full novelizations of games, which was, I hope, well recieved, at least 99% of the reviews were positive. (I count those saying they hated me because of what just happened in the last chapter as positive...

)
I have 40 stories up on fanfiction, but those of Bioware's games are the most recent and those I can say I'm proud of, the Dragon age fic was what started it and got over 300 reviews, which isn't so shabby. [link]http://www.fanfiction.net/s/5772539/1/From_dirt[/link]
Then the two most popular were the Mass effect 1 and 2 where the later got over 700 reviews! (I credit talimancers...though don't let that scare you off! It's not narrowly focused when it comes to characters! At all!

)
[link]http://www.fanfiction.net/s/6336055/1/The_shell_of_heroism[/link]
[link]http://www.fanfiction.net/s/6731678/1/Spirit_of_heroism[/link]
I've also just started on Dragon age 2, enjoying the challenge as it is.
[link]http://www.fanfiction.net/s/7566523/1/Chains_of_blood[/link]
I think part of what got those above going in terms of popularity was that there was always a conflict or tension of some sort going, mix that with modifications to the plot to make it smoother when written and the fact that no character was immortal and could actually die played a part, I believe.
I'm not excellent by any means, but I think those that keep reading enjoy it all the way through, which is what it's all about.

Anyone wishing to read and review is welcome, I reply to all reviews and questions.
