Ira Levin construed Deathtrap as a satire on the whodunnit genre. It should be noted that Deathtrap has many similarities to another play-become-film from a decade before, Sleuth (1972), which was also an over-the-top whodunnit parody whose drama all came in the battle of wits between two characters, one of which was played by Michael Caine (something that pressed the point of connection too far for many). The film is incredibly delicious fun. The plot is conducted with more twists and turns than a jar of pretzels and becomes increasingly more far-fetched with each turn taken, something that only ups the entertainment value the more over-the-top it gets.
The cast are all wonderful. Michael Caine absolutely shines and Christopher Reeve does a fine job of holding his own up against him. (Although, the show is frequently stolen out from both of them by Irene Worth as the Dutch psychic Helga Ten Dorp). At the time, Christopher Reeve was trying to shake romantic leading man status after the success of Superman (1978) and does a good job of doing so the scene where he and Michael Caine kiss for the first time brings a gasp of surprise from the audience, as much for the dramatic surprise it holds as it does for the fact we are seeing two men kissing it was one of the first portraits of open homosexuality on screen at the time (although is cut in many US tv screenings of Deathtrap today).
Director Sidney Lumet remains very faithful to the stage play and, bar a couple of minor exterior scenes, retains the single setting. He also creates great drama within that single set, such that one tends to forget that stagebound nature of proceedings altogether. The climax in a dark house lit by up lightening is remarkably tense, although the film peters out on another twist ending that is frankly incomprehensible (maybe it was simply that Ira Levin had built the play to such a fever pitch he could not find a way to cap it all off dramatically), this being the biggest failing of the film.
Director Sidney Lumet was responsible for a number of classic films including 12 Angry Men (1957), Long Days Journey Into Night (1962), Serpico (1973), Murder on the Orient Express (1974), Dog Day Afternoon (1975) and Network (1976). Within genre material, Lumet made the stark nuclear drama Fail-Safe (1964), the Catholic boys boarding school psycho-thriller Childs Play (1972) and the Wizard of Oz musical updating The Wiz (1978).
Other Ira Levin film adaptations of genre note are:- Roman Polanskis classic Satanic impregnation film Rosemarys Baby (1968), The Boys from Brazil (1978) about a Nazi cloning conspiracy, the android housewife takeover film The Stepford Wives (1975), the psycho-sexual thriller Sliver (1993), the remake of The Stepford Wives (2004) and the tv mini-series remake of Rosemarys Baby (2014).