My review was written in August 1989 after watching the film on Orion/Nelson video cassette.
"The Stay Awake" doesn't live up to its title, South African-made horror pic imported to U. S. video stores is a snoozer.
Moniker refers to a Britishism for a slumber party. The young heroines at St. Mary's School for Girls stay up all night in the gym as a stunt to help raise money for the institution. They're terrorized by a demon, calling itself Angel of Darkness, summoned up by a vengeful guy executed in the gas chamber in 1969.
Cast is good-looking but weak in the acting department. (An actor named Ken Marshall is credited, but he's not the U. S. thesp from "Krull" and tv's "Marco Polo".) Picture is so tame that when the requisite shower room scene is presented, one girl is even shown showering with clothing still on.
Monster shows up looking like a green reptile man, mostly limited to closeups emphasizing its orange eyes. Minor special effects are used in the final reel, but disposal of the beastie is unimaginative.