I'm not sure if this measure from Joe Hisaishi's "Hana-Bi" is correctly notated for a chord tremolo. What is the correct notation, and how should it be played?
The typical way to play this would be to alternate the upper two notes with the lower D. Here is one possibility.
It could also be played faster, in the reverse order (lower note first), or with the two lower notes alternating with the top-most.
A more typical notation would show the two parts of the tremolo separately.