This is better than anything I could ever do so I wonder if I should really be critiquing it.
Anyways, I like the fact that you used symmetry and a relatively new vocaloid. (Not many people that I have talked to know of IA.)
My next thought after that was did they have problems working on the face of the IA on the left (the original)? The face of that one just didn't look as natural as the one on the right. Unless you meant it to be that way then it's fine.
This is just plain beautiful and amazing I love it There's so much detail And I love their clothes and colors too It really suits them The background is also awsome I love how you got creative with it And their hair is very pretty too This pic just makes me speechless It's so awsome and amazing I sure could never do something like this, but you did a good job and I'm pretty impressed It's look pretty clear too The shadows, coloring and everything are very vivid and I just love the whole thing Nice job Keep up the good work