I think [Mike Nelson] found a winning place in the spectrum of showing too much and showing not enough that worked well enough. I don't think he hit it perfectly, but I think he hit a point that made it work well for me.

For an unabashed B-movie like this one, achieving the modest ambition of pulling off one killer horror scene is enough.

For every moment in which it feels as if Nelson is meeting the desires of his thrill-seeking audience, there are so many more that land like defanged nothingness. In the end, Beware Boiúna’s title winds up acting as its own consumer warning.

The human story is not strong enough to carry the film, while the creature itself is kept out of sight for so long that its eventual appearances eventually exhaust viewers rather than excite them.