First photo is from the 1982 Entex dealer catalog, the second is of the actual game as released. It is basically a re-design of Raise the Devil Pinball, but using a theme from a real arcade pinball game (Williams Black Knight pinball). It has 24 different skill levels, and also includes a tilt 'feature,' which is activated if you press the flipper buttons repeatedly too fast. It would seem that this game was released in very limited quantities. Entex actually had the opportunity to license the Dungeons and Dragons theme for this game, but they decided that D&D was just a passing fad and wasn't worth spending money on the license, so they contacted William's and licensed this instead (they also did this with Treasure Quest, turning down the D&D license a second time).
Thanks to Dan for the box pictures!