Hello,
I downloaded the offline installer files for HOMM3 Complete today only to find out you still need galaxy installed to use them - when you run part 1, it tries to find part 1 only to say it can't be found. The two files listed on gog are part 1 which was 803k and the .9GB bin file.

So, are there actual stand alone installer files anymore for this game like there were years ago that don't use galaxy?

No, you don't. Just download the EXE and BIN files (if there are more than one BIN files, you need all of them) into one place and then run the EXE.

Sometimes installers are just a single EXE file, but only if they're relatively small (a few hundred megabytes).

here the links listed on Library (Account) page
http://www.gog.com/downloads/heroes_of_might_and_magic_3_complete_edition/en1installer0
http://www.gog.com/downloads/heroes_of_might_and_magic_3_complete_edition/en1installer1
exe+bin. As Kerebron say, they must be in one folder. After downloading, check digital signature (valid) for exe file and run it in admin mode.

It worked for me, two days ago.

I had HoMM3, from the 3-and-4-complete retail CD, installed on my old desktop (Win 7 originally, now 10). Now I've installed - offline, I do not use Galaxy - GoG's HoMM3 (without 4) onto my new laptop, Win 11, and copied over my saved games.

One problem - the screen froze on me when I started the game, with a colored background and a cursor. Overlaying that was a Windows overlay prompting me to get DirectPlay feature. On clicking to confirm this, it installed in the background, but I had to cancel HoMM3 and start it again; and the easy (only?) way to do this was using the Windows key to access the power button and force a Windows restart.

PS I RIGHT-clicked the offline installer links on my GoG games page and selected Save Link As ... to download into my chosen folder (a new one). Then, after downloading everything, went into that folder with Windows Explorer to left-click the .exe file.

One tip I've had from these forums: steer clear of C:\Program Files and C:\Program Files (x86). My downloads (installers etc) are into a C:\GoGames from where I install to C:\GoG Games. If you've partitioned your drive then D: (or whatever) \GoG Games would be even better.

I disagree, I put them in the same file on my desktop and they still ask for the same missing bin file...

The files that worked for me:
setup_heroes_of_might_and_magic_3_complete_4.0_(28740).exe size on disk 804 KB (823,296 bytes)
setup_heroes_of_might_and_magic_3_complete_4.0_(28740)-1.bin size on disk 958 MB (1,005,043,712 bytes)

There's nothing to disagree with, because it's just the way it works. If it doesn't work for you, then it must be something wrong on your end, either with your software or your workflow (file names, program options, system permissions, malware, etc.).

CRC (CRC-32) for Eng offline GOG version
setup_heroes_of_might_and_magic_3_complete_4.0_(28740)-1.bin - e07698d3
(for exe file look at digital sign valid status).

Probably that because of installer location path. Two reasons.
First, non-latin path, on non-English OS, although it more critical for game installation path also applied for download files:
eg D:\Downloads\GOG\heroes_3_complete\... but not D:\Загрузки\GOG\ and no spaces or special symbols. The only differences for game path is better avoid also '_' to replace spaces, use '-'. Applied mostly for DOS(Box) games.

Second. Installer files located in Program Files, not in system user C:\...\Downloads\ or custom D:\Downloads folders. That mean exe file when launched been moved to C:\Users\...\Local\VirtualStore\, while bin file stay in first folder. Although Windows itself detect it is setup file (even by filename it can do that) and ask for admin rights, some 3rd party security services application can still block exe files lcoated in Program Files and forcely redirect them to VirtualStore folder and REGEDIT locations.

Also, turning off UAC do not turn off VirtualStore, but always redirect applications to VirtualStore instead. Keep UAC by default, start exe as admin, Windows should block desktop and admin permission promt windows appear - press Yes. That how it should be, do not turn it off.
Also, when that window appear - Windows should tell you it is trusted application from GOG Limited\Sp zoo with valid digital sign. Something wrong if there is no such message (corrupted download).

Hello everyone i need help. I buy H3 COMPLETE but how can i install HD MOD with WOG OPTIONS and from where, thank you ?

HeroesGL mod which one is included in HD+ mod is one thing. Almost not affect gameplay\ui, not replace any files.
HD+ mod is another. Include some interface and gameplay changes.
WOG is huge fan-made mod (there is also few map obj from Disciples?). Not related to HD+. And probably officail links are dead... although there is few heroes sites who host it and there is heroeswog community site. I doubt it is same team\site, but that not matter. You can download WOG as well as HeroesGL\HD+ mod there.

HOTA which one also use content from WOG is another mod. partially include improvements from any else (also from Disciples games)... something miss, add new.

There is still many sites host such mods. heroes communities or more general strategy games communities.