Continuity mistake: At the diner when Tsunoda and Retsuko are talking, Tsunoda pulls out a red phone with a white heart on it from her purse. In the close up she is pulling it out with her left hand and the phone is horizontal with the heart on its side. It then cuts to a wide angle and suddenly she's holding the phone upright with both hands.
Continuity mistake: After Ton bashes Retsuko for not getting her tea right, she sings some death metal in the bathroom before joining Fenneko back at the computers and they start talking. Between them is a pink cup with some orange scissors, and an assortment of writing utensils. They are fanned out, but show that the red one is closed to Retsuko with the black in the middle and the yellow closer to Fenneko. When the camera changes angles to show them both sitting there, this order of pens is flipped, with the scissors still being in the same spot.