It's amazing the level of detail you managed to put into this, in such a short time. A well-deserving member of the SWC's top three, for sure.
I feel Sirinian was a well developed character and the way his mindset changes from beginning to end is very smooth, as opposed to him suddenly changing. I love the way you characterised Celebi (had me giggling, especially the part where she complained about Dialga). I also liked how you dealt with the culture clash, making it seem somewhat more realistic than Lorelei and Sirinian totally understanding each other at once.
I didn't notice anything wrong with it and really enjoyed it - the premise of the story is interesting and you executed it very well. No complaints here!