When Shou dies, Tsubasa is totally inconsolable for several weeks at least, but when Hikaru dies, she is all up and perky in no time. How come? Sure, she went out on a "date" with Shou, but she hardly knew him, whereas Hikaru was as close to her as no other person could ever be. It's quite out of character for her.
The point here, is Tsubasa's reaction to Shou's death was .. too much, or so. She wasn't just mourning, she was lashing out at people around her and hurting her own self-confidence and generally a mess. Hikaru helped her learn to better deal with her emotions, and thus when Hikaru died (she was not perky, even at the end, she was still quietly mourning if you ask me, just not throwing tantrums and lashing out at people anymore) her reaction was just more subdued. - Chibi-Kibou
Yeah, I'm with the answer above. It's not that Hikaru's death is any less painful but that the shock/experience of losing Shou has helped her become more mature and much better at handling loss. She's hardly "perky" at the end, but she's not in a deep funk either.
How could Hikaru form that Figure in the end? Wasn't her energy depleted? And how come Tsubasa can't wake her up, but she suddenly manages to do so after she went to collect the bombs? How convenient.
As I remember it, Hikaru's energy wasn't depleted, but rather, wasn't regenerating properly. What she had left, they'd intended to burn off getting her to a research facility might be able to preserve her - instead she burned it making that Figure, thus killing herself. - Chibi-Kibou
Why did Hikaru tell Tsubasa she'd be with her forever, when she knew that was impossible? If she hadn't died, she would have returned to her home planet, so in the end she would have had to leave Tsubasa behind anyway. Why did she lie?
Denial. .. Or again, my interpretation, but it seemed pretty clear to me. - Chibi-Kibou
Well, Tsubasa doesn't tell Hikaru several things throughout the story, too. I guess they wanted to show that people don't do what would make the most sense...
The aliens can modify the memories of people, so nobody can remember Hikaru. Fine. But what about the artifacts Hikaru left behind? What about school material, such as tests and the like? What about that extra desk and bed in Tsubasa's room? What about the letter she wrote to Shou? And don't tell me nobody ever took any pictures of her.
This one I admit is mildly iffy.. but I always had it figured as said aliens doing a clean-up. The artefacts around the house are easy, the school material? Not so much, but then given the family moved back to a city hundreds of miles away at the end.. .. but yeah, that one wasn't so well dealt with I admit. - Chibi-Kibou
Yeah. I guess we just have to accept the Hand Wave here.
Why doesn't everyone think that Tsubasa's father is a bad parrent/outright Jerk Ass when Hikaru appears? "Well, I actually have twins - when their mother died, I torn them appart to make the mental scarring worse...oh, and I never speak about her in public."
Interesting question. In my country (Ghana) it's not uncommon to split siblings up to different foster parents if you can't take care of them all. But I don't know how it's done in Japan.
It bugged me quite a lot how useless DD was for defeating the Maguar. It made sense with the third, forth and later (when they're evolved so much they probably hardly resemble the "original model"), but what about the early ones? Even an alien, anxious little girl with absolutely no training is more capable of killing a Maguar. Damsel in Distress, very much.