Slow-paced if not tedious, and inexpertly written. Worth one viewing for fans of British sci-fi or 1950s sci-fi. I believe this is an American/British co-production but it has the distinct feel and atmosphere of a Brit SF flick from that era even though it is not on par with movies like Quatermass 2, X the Unknown, or Devil Girl from Mars.
Review of The Venusian
