It's true that the glowing orb doesn't exactly project any kind of menace. I just did a quick crude search for Simon's budget & came up empty. My guess is that this may have had a lower budget than an A.I.P. film made around the same time? The Dunwich Horror (another film I like) was made the previous year by A.I.P. & definitely cut corners in the visual effects for supernatural events, particularly in the latter portion of the production. Fortunately I enjoy both films enough that I suppose I give them a free pass in these respects. Agreed on the pentagram moment in Simon, that was well played.