Since the last version we have now installer part 1 and part 2, but both are the same installer (64bit), just that second "part" is named as if it was the 32 bit installer.

Then we also have the right 32 bit installer, which is smaller than the 64 bit one.

So: 64 bit installer part 1 and part 2 are the same 64 bit installer, repeated, just with different name and down the correct 32 bit installer (smaller than 64 bit one):

setup_prison_architect_64_12b_(13214)_(g).exe -> "Prison Architect (Part 1 of 2)" (460MB)
setup_prison_architect_32_12b_(13214)_(g).exe-> "Prison Architect (Part 2 of 2)" (460MB)

And also:

setup_prison_architect_32_12b_(13214).exe->"12b (32-bit installer)" (341MB)


I know it's a little error, but it can be confusing and as no one has reported this... Please, GOG, can you fix that when you can? Thank you very much!

Whats the difference 32 vs 64 installers ? And yes downloads are confusing. what to pick ? or if i need to patch earlier version. will the patch work

Yeah, noticed this problem, too. And the 64bit-installer (I guess) installs GOG Galaxy without asking for permission or anything:

https://www.gog.com/forum/general/download_prison_architect_what_is_what

Yes, the download page says:
Prison Architect (Part 1 of 2) 12b 460MB
Prison Architect (Part 2 of 2) 12b 460MB

yet they behave like:
Prison Architect (complete 32-bit version) 12b 460MB
Prison Architect (complete 64-bit version) 12b 460MB

However, the 64-bit version causes a System Error:
The program can't start because VCRUNTIME140.dll is missing

Well, that was long, long time ago, but the last installers for version 13f (which i hope will be updated soon to the last recent patch already on Steam) still have the same "problem":

-Prison Architect (Part 1 of 2) 13f 351 MB = "setup_prison_architect_64_13f_(17245).exe"
-Prison Architect (Part 2 of 2) 13f 351 MB = "setup_prison_architect_32_13f_(17245).exe"

Also, we have:

-12f (32-bit Installer) 341 MB = "setup_prison_architect_32_13f_(17245)_(g).exe"

That last one is interesting, not only says it is 12f version and it is not, because it is the same last 13f version as the 2 first installers, but also has the (old?) "(g)" of a Galaxy installer.

A total mess, even after a few more patches since the start of this thread a year ago... talk about lazyness... :P

Has anyone tried the newest version yet? I just installed "14k_(64bit)_(21856)" but now every time I start to start the game it says "The program can't start because MSVCP120.dll is missing from your computer."

Update:
It looks like the problem can be fixed by installing both the x86 and 64-bit versions of MS Visual C++ 2013.

I didn't try the latest version, but 13f was the same. This is the Galaxy requirement, and the game depends on it even if you don't want to use Galaxy. You can get both of these MS VCP 2013 redists by installing the Galaxy.

I don't use Galaxy and I was able to get the game to work. They just forgot to add the runtimes to the installer.

Yes, the game depends on the Galaxy runtime dependency but Galaxy itself is not neccessary. Steam version of the game doesn't depend on MS VCP 2013, it is a GOG feature.

Edit: 32-bit version requires MS VCP 2013 and 64-bit version requires also MS VCP 2015 which is installed along with the Galaxy.