It uses a mirror and lamps. The ghosts and effects are from a JAMMA pcb, the rooms are a mechanical diorama, when the lamps are lit it shows both, lamps off just the JAMMA pcb graphics.
just found this old pic of me when i did a raid (lol) mid 90s when i got a shead load of pcbs from acorn amusements in skewen wales . must of had about 30-40 pcbs at the time for a £100 , had loads of workers to , like rastan ghosts n goblins , scramble gaplus, super mario , bay route pac land sky kid bomb jack to name a few , oh happy days