I saw it the first day of its first run release at the Chicago Theater in Chicago in 1952. 'Bwana Devil' was the brainchild of radio director, Arch Oboler. - best known for the radio (and early live TV series) 'Lights Out'. Oboler's brother-in-law was Milton Gunzburg. Gunzburg was, I believe, the optician who connected the use of Polaroid lenses to the making of stereoscopic films.
In 1952, television was stomping out movies and movie theaters the way rogue elephants could destroy villages. Hollywood was searching for any gimmick it could use to bring people back to the theaters. Cinerama, a cumbersome early widescreen process had come on the scene. It produced an 3-D like effect. That opened the door for Gunzberg and his brother-in-law. They called their process Naturalvision, raised some money to demonstrate the process, and produced 'Bwana Devil'.
While the story and production values took a back seat to the illusion of depth, the picture was a hit. It was quickly followed by 'House of Wax' and others. Most producers opted to exploit the stereoscopic effects rather than make good movies. 'House of Wax' was one of the rare exceptions. After about a year, audiences tired of the shoddy productions, and Naturalvision eventually disappeared. Into the void Fox introduced CinemaScope, a flat wide-screen process, and helped stem the sinking theater system.
I imagine seeing 'Bwana Devil' in flat projection would be painful. But for those of us who saw it with pristine prints, and quality projection, it was something to behold. Lions leaping off the screen into our laps was something few of us would forget.
It has taken another fifty years for 3-D to return. Today's producers seem not to be making the same mistake as those in the early fifties. I hope so. After all, 3-D is so much more fun than flat.