A definite improvement over Thunderbirds Are Go (not that Thunderbirds Are Go doesn't have it's own, at times, surreal charm). Thunderbird 6 is more like a typical Thunderbirds episode. Plus, plenty of Lady Penelope, Comedy-re-- I mean Parker, along with Alan (was he really that popular?), and the inscrutable Tin-Tin. Brains and the rest of the Tracys including the poor space marooned John have their share of screen time too.
Even now the miniature work on the sets still impress. The movie's violence is surprisingly cold blooded; no worse than any typical contemporaneous western and no blood obviously. Plenty of explosions. It should be kept in mind that when this was made it wasn't a children's movie, it was a family film. Not a bad swan song for the Thunderbirds.
6/10