Well, ok then, so it is horror FPS similar to Blood, Witchaven and Undying... or somewhere in between
If it is "shooter", not RPG (with improving stats and everything) then what were you shooting with? Modern pistols and guns or with arrows and wizards staff and similar spell casting?
Also check:
Montezumas Return,
Amulets and Armor,
7 paladins or something,
Shadow Warrior...
edit:
Also, if you there is hope that game is on mobygames, check
this filtered search and narrow it done by year and system or change filters entirely... you'll find more games to add to your list at least
oh yeeah, also check
KISS game