This version was never worked on. From Ross Sillifant's interview with graphics artist Pete Lyon, who worked on the Amiga version:
Pete Lyon: "At that time, I would have been using a PC and DPaint to create the graphics. Any conversion to the ST would have involved mixing down the palette from 32 to 16 colors, which I never did. I really don't know what happened there, whether the conversion was cancelled for commercial reasons or something else. We were all getting involved with other projects and did not work in such an integrated way that I would have been privy to any such considerations. There always seemed so much to do that my attention slipped in a blur of activity. I can't really be of much further help on this matter, I'm afraid."
Ross also found this information from Joystick, a French magazine from an interview with Steve Bak:
Joystick: But Fright Night has been developed on Amiga, yet...
Steve Back: No, it was not only on Amiga. I worked only on this version, which is a slight difference. The reason is that the boss of Microdeal wanted the Amiga version in first, and wanted a software that takes advantage of the machine. That's why I made much bigger sprites (100 pixels high) and that I would not have done normally. It's for this reason that I didn't want to convert the game on ST - too much work compared to what I could get something useful. If I had to convert ST myself, I would not have created with such large sprites."