They don't resemble piranhas at all. However, they possess a ravenous appetite similar to them. Rupert Harvey directed Critters 4, which was written by Barry Opper, Joseph Lyle, and David J. Schow. The cast includes Don Keith Opper, Brad Dourif, Angela Bassett, Anders Hove, Terrence Mann, and Paul Whitthorne. Peter Manning Robinson composed the music, and Thomas L. Callaway handled the cinematography. The initial run of "Critters" movies produced four films in just six years, but the quality steadily decreased until it hit its lowest point with this fourth installment. The humorous moments that used to be interwoven with the violent actions of the creatures are absent, replaced by a lackluster imitation of “Alien” where the Critters become minor characters in their own series, essentially losing one of their most effective attacks—the ability to launch deadly spikes from their bodies. Despite these shortcomings, the cast is somewhat noteworthy, featuring two actors who have been nominated for Oscars and seemingly working just to earn money. The straightforward spaceship interior design works well with the "stalking" storyline, and the cinematography adheres to genre conventions in a visually appealing way. Ultimately, though, this film feels like something only dedicated fans need to see—those who initially enjoyed the first movie back in 1986. It earns a rating of 3/10.

Source on TMDB