The Dissolve by Keith Phipps

In form, Phase IV isn’t that different from monster movies of old, though the ants never grow to monstrous size. In execution, it’s much more striking, offering a study in contrasts between ants and humans, and one that doesn’t always reflect favorably on the humans.

The A.V. Club by Ignatiy Vishnevetsky

It’s a movie that seems to have been designed more than directed, and edited around principles of color and line, rather than around performance or plot.

The New York Times

In making his feature directorial debut after a succession of distinguished film titles, graphics and short subjects, Saul Bass, with the aid of special insect photography by Ken Middleham (Hellstrom Chronicle), has fashioned a pictorially persuasive adventure.

Chicago Reader by Jonathan Rosenbaum

So-so ecological SF thriller from 1974 about superintelligent ants.

Time Out

Humankind's fate is left in the hands of several unusually inept and colourless scientists, the ants get the works from the special effects department, and original ideas (so often a casualty in sci-fi cinema) take a back seat.

Variety

This one didn't get the bugs worked out before release. It's another in the Hollywood cycle of films based on every kind of creature enlarged by radiation.

TV Guide Magazine

One would think that director Saul Bass, whose credit sequences for such films as Hitchcock's PSYCHO are nearly as interesting as the films themselves, could pump some energy into this potentially interesting premise, but all he comes up with is an overly intellectual bore.