The Hills Have Eyes Movies: Classic Timeline
The original Wes Craven timeline consists of his 1977 cult classic and its widely panned 1985 sequel. While the original remains a landmark of '70s horror cinema, the sequel is considered one of the worst horror sequels ever made.
Craven himself disowned Part II, which he only directed out of financial necessity after the poor reception of his previous films. The sequel is infamous for excessive padding with flashbacks to the original film and features a notoriously absurd flashback sequence for a dog. Most fans consider the 1977 film a complete story on its own. You've been warned.
There are 2 other watch orders available - see the links up above.

The Hills Have Eyes
When the Carter family's RV breaks down in the remote desert, they become trapped and terrorized by a clan of savage cannibals hiding in the nearby hills.
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The Hills Have Eyes Part 2
A motocross team ventures into the desert to test a new super-fuel, unaware that their guide Rachel has a dark connection to the area's dangerous past. They soon find themselves facing the same deadly threats that plagued previous visitors to this remote wasteland.
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Other Film Series
It
The Losers Club faces off against Pennywise, a shape-shifting entity that terrorizes the town of Derry every 27 years.
Nightmare on Elm Street
The iconic horror franchise following the burned child killer Freddy Krueger who stalks teenagers through their dreams.
Prom Night
A horror franchise that blends slasher and supernatural elements around the prom night setting, featuring mostly standalone films with one connected supernatural subseries.
Romero's Living Dead
George A. Romero's groundbreaking zombie saga, featuring classic horror films and several reboots.
The Exorcist
A horror franchise exploring demonic possession and faith, beginning with the groundbreaking 1973 film about a young girl's terrifying possession.
Unbreakable
M. Night Shyamalan's grounded superhero trilogy following ordinary people who discover extraordinary abilities, culminating in an unexpected crossover.