James Atkinson’s review published on Letterboxd:
All monsters attack! Is a huge let down in the series, especially after the greatness of Destroy all monsters. I know I'm not the target audience here and the story of the kid overcoming his fears is not too bad but the whole thing was just very annoying.
This one is a let down due to being full of stock footage as the special effects guru was sick during filming. The new monster Gabara is one of my least favorite designs and he's mostly up against Manilla who continues to be useless and is probably my least liked in the whole franchise.
All Monsters Attack! Will work for very young audiences, but just wasn't for me.