Already having the German (UK-F-Ger) retail version as well as the GOG version of VTMB. I availed myself of the opportunity (Halloween sale) of getting the Steam version as well. I had hoped that it would be a true vanilla version with all of the copy protection stuff removed at the price of the game being tied to Steam. After the first launch, I was pleasantly surprised. A (supposedly) vanilla version that works with Win10. However, it is not. It uses the same exe and engine stuff as the GOG version.

What's the difference between the retail version and the GOG/Steam one? You said the engine has something different in it?

Because Windows doesn't support the original copy protection of Bloodlines anymore, all available versions use some kind of cracked executables. If you really want the original though, just download the Unofficial Patch and look for files with the 12 ending...