I liked the demo of "The Long Reach" so I was interested to get the full game.
As the demo is Unity and includes both 32 bit and 64 bit binary (as usual),
I assumed that the full game provide the same.
But it does not - as one may see (if not drawing wrong conclusions from the demo)
on the GOG product page.

I managed to create the 64 bit version which seems to run ...
but hesitate to give the easy way here before the developers confirm that this is no problem.
And ideally they may provide it with an update in near future.

So I contacted the devs and will provide any further detail I can get below (incl. date).

JMB

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For further pieces of information after the main posting (on 06.09.2020):
- ... please hold the line ... ;)