Dozens of officers were sent to the Star City complex at around 1730 GMT on Saturday after reports of a mass brawl involving youths armed with machetes at a Birmingham cinema.
Local police said up to 100 teenagers were involved in the "major disorder," where people were armed with machetes.
The massive brawl "may be the worst thing" the police force has ever seen, a senior police chief said.
After the incident, the cinema chain confirmed on Sunday that Blue Story, a film about gangs, will no longer be shown in any of its 91 outlets in the UK and Ireland.
Armed police were deployed to the scene, drawing Tasers to restore order following a "very hostile response."
Chief Superintendent Steve Graham said the force used by officers was "proportionate", adding that the disorder took 90 minutes to break up because police were not "heavy-handed".
Officers were left with facial injuries, and a knife was recovered from a nearby roundabout.
Investigators said they were working to understand the reason behind the disorder, which bears the hallmarks of an organised fight between rival groups.