http://www.gog.com/forum/blood_omen_legacy_of_kain/the_character_cuts_the_air_by_itself_and_does_not_move_at_all There is more threads on that sub-forum as i remember.
Strange... But first that cross mind about that - some autohotkeys tools, bundled with input devices drivers some tools to preset something\triggers (usually for mouse).
Or connected gamepad issue. Using Xinput is possible on this release but it be anyway detect by game as dinput. Hot-plugging not supported, must be manually rebind in settings before start a new game. Want play on KB - unplug gamepad.
Or maybe some fixes are installed by you. GOG version not compatible probably with all of that outdated fixes. Current solutions - already build-in DirectX wrapper by GOG (usually directdraw, now also xinut\dinput wrapping) or GL wrapper by Verok. Look at forum section from link above - there is threads about that wrapper.
Reinstall clean GOG offline version and play as is with official wrapper. Should be fine. Then - optionally - install unofficial OpenGL wrapper.
Both variants not compatible with old modded exe or bink patches.
If you not want GL wrapper - you can download game via GOG Galaxy. Always do verification after downloading - at least twice.
Also, sometimes offline versions better - but installing them still allow you to add and recognize them to GOG Galaxy as GOG version.
Using Galaxy - require galaxy.exe set to admin run.
Using offline or starting Glalsxy build directly from exe - set kain.exe to admin run.
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Initial release work well for me. But someone report of black screen and freeze issue. Although it is differ problem, in your case game can freeze too - if you go to controls (and you should go to controls anyway).
Did you redownload actual build? It should be from 7 oct and not from 29 sep (23 in installer digital sign). Or, again, for Galaxy - verify game files.
Also, make sure clean English version is work before installing any language packs (unofficial spanish translation).