The movie is based on a story for a video game that BFG has in development.
Originally entitled "Backwater".
In the video game and some versions of the script, Ray Sawyer was nicknamed Mr. Jangles because of his keys. When you hear them jangling, you know he's near.
Fangoria Magazine did a behind-the-scenes story during the making of the film while it was shooting under the title "The Reaper". The title was changed to "Venom" shortly before it's release.