(Regardless of content) I don't know about you, but to me when you sell a parody you also do it on the girl's whole design, so when you untie her hair, strip her naked, it's black and white, that kind of defeats the purpose, all that's left is a regular Napata girl called Mika and whatever the author got of her personality from the game or whatever. In a way reminded me of this
fried: The Mika in the cover is the Mika the doujin started with.
fried 2: I know about the card, but when a design is already simple as is and the author is a (awesome but still) sameface, it's best to retain as many features of it as possible, like he did with Rin Shibuya. I don't think it's too harsh of a criticism.
Thing is though, there is an incarnation of Mika from the games with her hair down. The nature of the source material of the parody has the idols in variable hairstyles and clothes depending on the card. So in the end, you could say that this doujin panders to the crowd who like that particular version of Mika featured in said card.
Said card for reference: http://cgdex.project-imas.com/cards/frameless/3404701.jpg
edit for further replies: That's not the point though. I was just addressing your point of the Illusion that this is Mika from Im@s:CG being lost due to her hair being untied.
Normally, I'd agree to the sentiment that if the doujin artist takes liberties with the character design outside established canon, then the doujin artist might've as well invalidated the status of it being a parody and turned it into an OC creation. But we do know for a fact that Mika does untie her hair every now and then. There are official cards and comics depicting her as such. Therefore, the assumption that the girl in the doujin is still Mika isn't lost.