Hey folks, just to provide an update here.
I had the same problem with Slain back from Hell. Bought it on sale on GOG, installed on my new Acer Nitro 5 laptop (bougth in late 2019), game installs and works just fine until you die and get stuck on "you have been slain" screen.
I have read all comments in this thread, people saying that game works on one computer, not in the other.
Then I moved to install the same game on my old laptop, Lenovo Ideapad 360 from 2011 and the game WORKS JUST FINE. I died multiple times in the first blood pit just to confirm it was not a mere coincidence, and to my surprise, everything went just fine.
Not sure what is going on with this game, but given that latest patch was put out in 2016, I'm pretty sure devs have abandoned the game.
So, in a nutshell, give this game a try on older computers and post your experiences here.
Who knows... maybe it's a drivers update somewhere, maybe a new feature in new computers, maybe a Unity function tha is deprecated since game latest release, something that only a dev can check out on newer hardware (I don't expect that to happen)... we will never know until we test it thoroughly and post results here.
Like lots of people, I have the same issue on a win 7 64 bits. It works fine on a Win 10 up to date. Usually, I don't use Galaxy but it allows to donwgrade the version of the game. And... surprise it works again in 1.25 version of the game. I lose some improvements but now it works. I hope it may help.
Also, using the GOG feature to install older game version works, if you downgrade to 1.25 as Lignorant mentioned.
In case you are not aware, open GOG, go to the game page, select Settings icon -> Manage Installation -> Configure...
In the new windows that pops up, move to first tab Installation, unselect Auto-updates option and then select the specific version you want to downgrade to. After download and install, click Play (do not click UPDATE button as will revert game back to latest version).