I ask because I was hoping to run this game on a linux aarch64 machine through box64, but then I realized this is an old 32-bit only release.

(box64 iis software on aarch64 (arm64) which allows you to run x86_64 linux executables)

Or is there an x86_64 linux binary release I'm not aware of?

It works without issue on 64 bit linux system.

Edit: Sorry, I missed you want run on ARM. No idea then, I have zero experience with these. But I see there is Box86 too for 32bit applications.