The war machine factories have been pumping out new units for the last three decades - but where are they getting materials?
They have a handful of robots following Angela around, collecting all the scrap metal from the robots she cuts up.
If the city is such a wasteland that nothing grows there, where did the robots get eggs for Haruka's breakfast? And how/why do the birds she sees in the first episode live there?
When the seawater receded before the tsunami, the whole area was completely barren and dry when the group woke up. Where did all the seaweed/algae/barnacles go? And how did that big a landscape dry up completely overnight?
How is it that Honi is smart enough to fool Kanato and his other robot friends for years, yet dumb enough to conpletely misinterpret his last command? The other robots show much more freedom in their thinking.