But the controls, terrible. Unfortunately, GOG screws up again, and only provides the basic original UK version. But if you want to remap your keys in game using the enhanced US version, the help on modifying the GOG install to do so described on the GOG forums was no good. It ruined the speech audio on my Win 64 machine. However, the following approach works fine:
Changing key-bindings in Realms of the Haunting (UK release)
I now have normal WASD FPS controls. Yay! Mapped Q and E to turn left and right. Also, holding down both mouse buttons gives you mouse free look ala standard FPS's of today.
I just used AutoHotkey to remap the bindings. It's easy to use and can toggled on/off with a few mouse clicks. I've been using it for years on games that don't allow me to rebind keys to my preference.
Realms of the Haunting is a pretty cool game though. It combine first-person gameplay with point & click adventure in a way that few games have. I didn't care for the combat, but I loved exploring that mansion.