You can use the Goldberg Steam Emulator to run the game without Steam.
To run it on XP you'll need to use a crack with the older build of the game or a modified build of Goldberg with XomPie or OneCoreAPI ws2_32

For Fusion (Vista+?) you can use SmartSteamEmu and possibly goldberg (untested)

Sorry DosFreak, but I have no idea what you are talking about.

Serious Sam BFE on PC is sold only through Steam. So no matter which option you choose, it would be cracked Steam version. Alternatively you can try Xbox360 version, with degraded graphics, which probably can be emulated now.
Maybe someday Croteam will wake up from their slumber and re-release it on GOG.

I was surprised to find that the Serious Sam Collectection wasn't released on PC (I have it on the XBox 360). It's not a great collection, as it has the PC version of the first game (both encounters), instead of the version for the original XBox (the XBox version is one of the very rare times when a console port is improved over the PC version), and the collection doesn't include Serious Sam 2. But it does have Serious Sam 3 and it's DLC.

Was the PC version of SS3 ever released on a disc?

Kerr Avon wrote on 2021-02-12, 17:22:

Was the PC version of SS3 ever released on a disc?

It was (you can find it on eBay), but it just had a Steam key and Steam installer + data for Steam to read from instead of downloading it on the disc to my knowledge.

Corey wrote on 2021-02-12, 04:56:

Sorry DosFreak, but I have no idea what you are talking about.

You can play an older cracked copy of the game or the latest version of the game with a steam emulator.
Serious Sam BFE is also included in Serious Sam Fusion which you can also use a steam emulator with.