The zombie movie “Dead Rising: Watchtower” might hold rewards for people who have spent hours immersed in the video game series on which it’s based. Judged as a free-standing film, though, it’s a time waster devoid of the wit and depth of other walking-dead fare currently available — see, for instance, the new CW series “iZombie.”

‘Dead Rising: Watchtower’ Not rated Available Friday on Crackle

The film, offered on Sony’s streaming service Crackle beginning Friday, has some recognizable stars, but they are trapped in a slim story padded with lots and lots of flesh-eating.

Rob Riggle from “The Daily Show With Jon Stewart” is Frank West, the central zombie killer in the original “Dead Rising” game. Here, though, he’s a boorish guest on a newscast, providing unhelpful commentary during coverage of a new zombie outbreak. It’s a conceit that should have been funnier than it is.

Most of the actual zombie fighting falls to Jesse Metcalfe (“Dallas”), playing an online news reporter trapped in a quarantine zone, and Keegan Connor Tracy as his camerawoman. Zombrex, a drug that will be familiar to game players and is used to keep zombie symptoms in check, suddenly ceases to work, and hordes of infected people who had been able to function as humans turn all chompy.

Meghan Ory (“Once Upon a Time”), Dennis Haysbert and Virginia Madsen also turn up as the conspiracy-filled story lurches along bloodily but not very coherently. The “Dead Rising” video games put a premium on making zombie-fighting weapons out of ordinary objects, and there is a fair amount of that here for fans of the game. As for why the subtitle is “Watchtower,” you’ll have to hang on until the very end to find out, and only those fans will care.