If you loved Phantasm, try Phantasm IV: Oblivion
A bridge between a film you've already seen and one most people haven't. Phantasm IV: Oblivion has roughly 3.4× fewer votes than Phantasm — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Don Coscarelli, and they both carry the dread mood tag, and they sit in Horror / Science Fiction territory. If that's the register that drew you to Phantasm, the second film will land in a comparable space — through a different lens.
dread
What Phantasm IV: Oblivion is
Desert highway at dusk with a rusty sedan speeding by. Mike and Reggie on the run from the Tall Man. Don Coscarelli helms this 90s horror sequel.

