** contains spoilers **
Let's be honest if you compare it to Superman I & II it fares quite badly, as many films would, but it is far better than the last 2 Superman movies.
Supergirl travels to Earth to recover the omegahedron, the power source of her home planet that is being used by Faye Dunaway as the over the top witch Selena bent on taking over the world during Superman's absence sorting out an intergalactic war. It IS pure high camp, with Dunaway, Brenda Vaccaro and Peter Cook all hamming it up well as pantomime villains.
The only other characters who are memorable are Maureen Teefy as Lucy Lane, Marc McClure as Jimmy Olsen and Peter O'Toole in the final part of the movie.
Supergirl herself never quite gets to show the strength from the comics. There is the nutkick to one of the truckers who confronts her and wants a good time, a few minor set pieces but no real Superman style KAPOW moments.
It is very effects driven at the end as Dunaway unleashes her black magic. Supergirl despatches a minor invisible demon, half-cousin to the monster from the Id from Forbidden Planet then gets transported to the phantom zone. Her escape from the phantom zone aided by O'Toole who dies just as they near freedom.The final set piece with Selena bringing forth an elemental demon is a little weak, it looks OK but it would have been better if the creature was more physical and better animated and not just a growling shadow.
All in all I did enjoy it and Helen Slater was good in the role apparently turning up for the casting session dressed as Supergirl. What a shame that the extras that appeared on several versions, notably the 2 disc NTSC version, including the audition clips were not included here. It is always annoying when a studio releases a DVD of a film over 20 years old and does not make it a definitive version, it smacks of a possible future re-release. There were rumours of a Super series similar to the Planet of the Apes ape-head set featuring the 4 Christopher Reeve Superman movies, Supergirl as well as the 50's serials with George Reeves and maybe some of the cartoon series. I'd hate to think that Warners would pull a stunt like that.
Jerry Goldsmith's theme works well and is a five star score with slow romantic passages as well as the main Supergirl theme and the sinister phantom zone themes.
If it had the "Making of...." and a few more extras it would be worth 5 stars, as it is I would give it a generous 4 stars as at just under 2 hours it is good value for money.