Metal Heart(2004)

Metal Heart

Meet Min Woo. A normal 18 year-old high school boy. Well...normal except for being a total otaku. He does what every good little otaku boy does. He collects figurines and toys, wins prizes at cosplay contests and is a two-time champion of the fighting game "Metal Heart". Unfortunately for him, his social life is dominated by girls telling him to get lost, since his otaku-ness might be contagious.
But after an accident while he is invited to participate in the playtesting of "Metal Heart 2", the main character to the game, Min Sia, materializes in front of his eyes at a cosplay festival. And now, Min Woo has to win Sia's heart in a real-life dating sim game with the fate of the world in the balance. Ok, so maybe not the world, but at least the fate of the company behind "Metal Heart 2" hanging in the balance.
And who is this girl Nuri who appears following Sia, who claims to be Min Woo's childhood friend...