Released at the end of last year, it has been a box office hit locally -- despite only getting a short run in cinemas -- and has raised hackles on the mainland amid increasing fears in Hong Kong over Beijing's tightening grip.

The series of five short films, each by a different Hong Kong director, depicts the city in 2025 where young children in military uniform prowl the streets, the local language of Cantonese is disappearing and one protester goes as far as self-immolation.

The filmmakers say they feel it was only given short sporadic runs at cinemas across Hong Kong after its release in December due to political reasons, as it was commercially a runaway hit, selling out at the cinemas where it was shown.