As of this writing, there are 3 reports on protondb.com on Night Trap for Steam-Play/Proton. Two of them claim it's unplayable (which it is, out of the box) and another one requires you to have a Windows 7 installation somewhere ready.
This is due to the Windows Media Foundation files being missing.

Luckily there's another way thanks to some fixes that had to be done to get other games working.
I tried contributing these to protondb, but they require my Steam profile to be public. No thanks.

Enter these commands in your Terminal and the game should more or less run:

And then delete the mf-install folder whereever you ran the commands. I ain't risking you entering some rm -rf command.

These are the quick and dirty instructions. It's all thanks to the people that contributed to the mf-install repo on github.
I definitely wouldn't want you entering random commands from the Internet, so check out the github page in the table above yourself to see what it's all about.

-- Marco