Hard to know where to start with this mess. The basic premise, including the not so shocking denouement, could be summarized on the back of a postage stamp. To summarize the indignities inflicted on the poor benighted cast by the clueless scriptwriters would take longer. Absurdities abound - the Alphans head out into -75 temperatures attired for a minor snowstorm, then much of the away team is apparently lost and Paul tells Alan there's nothing he can do, before launching a rescue mission in the next scene. There's more, but I risk spoiling what surprises there are.
Brian Blessed's comedic talents are now well appreciated, and it's a pity that he was required to recite his ridiculous lines straight. John Shrapnel, as an intergalactic Shakespearean fool, has an almost impossible task with this material, but Shrapnel and Landau do manage to conjure two or three moments of real feeling. In general, the cast acquit themselves well against almost impossible odds. The 4 is for them.