Nightmare Fuel: If you live where a major earthquake is expected, this could very well cause some mental discomfort.
Shocking Swerve: Mirai's descent into apparent hallucinations after Yuuki's sudden death was not particularly well-received by a portion of the viewership, as it marked a shift in tone from objective and realistic to either supernatural or subjective (Mirai's POV). Yuuki's death itself also appears to be a case of this at first; had Yuuki suffered a cerebral hemorrhage as suggested by fans, however, his condition would likely have deteriorated that quickly.
What an Idiot: Kento risks his life to save a mass-produced reconnaissance robot.
Woolseyism: In the Japanese version, Yuuki and Itsuki call Mirai the phone alien. The English dub tweaks it around to make it sound more alien-like, having them refer to her as the "Cell phonian," which is much more creative and sounds just like something a seven or eight year old kid would come up with. It's the same thing with "Frogworlder" and "Sergeant Snack Time."