There are filmmakers who start big and get bigger, their project mushrooming ever larger as new ideas, characters and scenes enter their landscape.

Then there’s Tim Fehlbaum.

The Swiss writer-director — he previously made two indie sci-fi films — started really big. He was going to capture from every angle that fateful day of Sept. 5, 1972, when eight terrorists from the Palestinian militant group Black September infiltrated Munich’s Olympic Village and attacked Israeli athletes, killing two and taking nine hostage. (All would end up dying.)

Police officers, Olympians, journalists, civilians, government diplomats — Fehlbaum and his co-writers Moritz Binder and Alex David would cut between them all, creating a Rashomon for the Olympic era. The seismic event — a brazen act of evil on the world’s biggest stage — demanded a big cinematic treatment. Fehlbaum would give it nothing less.

But then a little voice called financial reality piped up. “We had a...