Good, but can be improved.
I really liked the art style in this flash. It seems sort of familiar, but unique at the same time. I assume I don't have to get into how horrible the sound quality was and how cliché the plot seemed, since you did mention that you were just testing out the art style. The background looked great, but it seemed too still. The lightning effects were really good, but it needed a bit of cloud movement. Maybe even a little bit of a wind effect on the tree branches, if you really wanted to get into it. The few drops of rain hitting the boy in the face came out good, but the pouring rain seemed kind of cheesy. The only other things that seemed a bit off with the graphics is the fire and the blood hitting the window. I can't really but my finger on it, but they seemed like they lacked a bit of detail, compared to the rest of the flash. On the subject of detail, I really like the way the characters look. The girl's features are a bit...well, grotesque, which really seems to fit her rather nasty attitude. I don't know if you were aiming for that, but either way it worked out nicely. As for the music, I think that it really fit the genre of the animation, and the style very well. It kind of really pulled it all together. Lastly, I like the way it feels sort of unfinished at the end. It doesn't get into how or why they are killed, and it also leaves room for another little story if you really felt like making it into a mini-series or anything spiffy. Well, I believe that sums up all my thoughts and opinions. ^^;;
On a side note, I'd like to add that I enjoyed the sound of the blood hitting the window. I don't know, it sounded silly and it made me giggle.