StarCrash, starring Marjoe Gortner and Christopher Plummer, believe it or not.
Highlights include:
* Plummer, as the evil emperor, aboard his enormous battlestation in deep
space: "By sunrise we'll have conquered the galaxy!"
* Gortner, as the prescient alien, explaining as he lays dying why he got
shot when he knew it was going to happen: "It's against the law to change the
future."
* The evil space station looks like a giant hand. When Plummer cries "Prepare
to attack!", it forms a giant fist.
* The good guys reply by firing "torpedoes" at the space station. One crashes
through a glass window into the throne room -- causing not one iota of
depressurization -- a hatch pops open and out jump 2-3 soldiers who start
shooting laser rifles at people!
Oh, and I think David Hasselhoff is the young prince or whatever that the
good guys rescue.
Patrick