conspicuously lacks a brain either before or behind the camera, and substitutes instead gallons of fire fighting foam a la [the Dr Who story] Fury from the Deep
(David Scott, DWB, 1992)
It is amusing that the story opens with the entire crew of Moonbase Alpha doing jigsaw puzzles; it is less amusing to find that the pace of the story doesn't improve much from there
(Anthony McKay, DWB, 1992)
The sort of Sci-Fi hokum that the series got a -mostly undeserved- reputation for providing. Pure nonsense, obviously written because the production team had got hold of foam generating equipment, and thought a story could be written around it.
(Richard Houldsworth, TV Zone, 1992)
Most 60s and 70s SF TV series did a 'foam machine' episode sooner or later and this is 1999's. As you would expect (in Year One anyway) it is handled a bit more intelligently than your run of the mill 'foam machine' episode. B-
(Chris Bentley, SFX 20, 1996)
Despite its cheesy 1950s title, Space Brain is one of 1999s most effective stories. The antibodies are represented by mountains of soap bubbles. While this staging solution makes for an inherently silly looking threat, as if a washing machine had gone out of control, the momentum of the final scene and Landau's performance keep the episode from losing credibility.
(John Kenneth Muir, Exploring Space: 1999, p71-72)
A huge alien entity steals the mind of an Eagle pilot in order to communicate with the Alphans. Some good atmosphere in this otherwise fair segment. ** (fair)
(James O'Neill, Sci-Fi On Tape, p272, 1997)
Space Brain is intensely dramatic, highly enjoyable and is one of the most visually memorable episodes. However, it is several notches below other episodes in terms of intellectual challenge and rewarding story content. Watch Space Brain for the sheer spectacle, and for the sincere performances. Don't watch it if you're seeking a profound script. 7/10
(Bob Wood, The Future Is Fantastic, 2001)
Again, this episode is completely over the top. It’s fun, but only just. 2/5
(Alasdair Stuart, SciFiNow #10, 2007)