For humans only. Non-humans banned!
Why it is hard sci-fi
A grounded first-contact film set in Johannesburg twenty years after a derelict alien ship has stalled over the city. The aliens are refugees in a slum. The film treats the situation as a documented bureaucratic disaster and follows a Multinational United officer whose paperwork-driven eviction of the slum goes wrong. The biological transformation arc is rigorous about what it would take to reverse-engineer alien biotechnology.
Science inside it
Xenobiology with a working compatibility model. The fluid that transforms Wikus is a fuel for the alien command module that drives matching biology in any organism that absorbs it, which is also why their biotech rejects human users. The film also leans on real apartheid-era forced relocation procedures for its bureaucratic spine.