John Carpenter was 24 when he shot one of the most influential films in movie history in just 20 days, on a budget of just over $300,000, for the apparently meagre salary of $10,000, a cut of the profits and his name above the title. Looking back, a quarter of a century on, it was probably the best deal he ever made. After a faltering opening run, Halloween quickly became a critically acclaimed box-office smash that went on to gross over $50 million and spawned a raft of sequels and an entire industry of mostly inferior slasher movies.