Yay, you got it up! :D

Firstly, I like how it took a while to reveal what the main character's species was. I love to write my stories that way too, and drop little hints as you did for the reader to try to form an image with. Before it was revealed that he was a pikachu, I was envisioning a minccino.

It's interesting to see how a pokemon would work in a regular society in a non-trainer role, especially one who has lived there presumably for years and knows nearly everything about the city and how to avoid (or get themselves into) trouble. The little comments that were made in the narration which indicated his knowledge of human life was very believable. I especially liked his craving for human food, such as the Double Diglett Bites. xD So funny. I think the suspense was done really well when the shop worker was closing in on him, too. The whole part at the end has left everyone hanging, I'm sure, and I wonder if the mew was visiting him on purpose or just happened to find him there. xD I guess we'll find out!

Overall it was very well written and engaging, and I look forward to more. :D