Good question! I've got to give a lot of credit to the folks at Ice Pick Lodge who made Pathologic. Pathologic is a relatively obscure series, but for my money it's one of video game's most evocative experiences. It's a super compelling moral roleplaying experience. Another game that had a lot of influence was Undertale (setting and more moral roleplaying elements). Also, there's a lot taken from the Italian Epic of Dante's Inferno (and a little from the two other books). More broadly the game is influenced by absurdist philosophy and Emersonian individualism in its thematic goals.