Humour!

Couldn't help but think while watching this film as it reminded me of the old B&W "Ealing School" films, crossed with the film "Keeping Mum".
Thinking more, I could imagine the dad being played by Sir Alec Guinness, Peter Sellers as the Uncle, Irene Handle as the mother and Herbert Lom as the brother.
Perhaps Ji-Woon Kim the director watched old British films when he was young?
Enjoyed the film though, very good!

You do not need a parachute to skydive. You only need a parachute to skydive twice