At 9.20pm on Saturday 5 October 2013, six men in their late teens went into Premier Stores on Queens Road in Cheetham Hill.
They told staff to go into the back of the shop, while two of them went behind the counter and took three bottles of vodka.
As a member of staff attempted to stop them from leaving, one of the group threw a full beer can at him. He suffered only a minor bruise to the back of his head.
As the six men left, one of them dropped one of the bottles of vodka which smashed on the floor.
They ran from the shop and turned right towards the Fairy Lane estate.
All six men are white and in their late teens. They were wearing gloves and had their faces covered with hoods pulled up.
Police have released CCTV footage of the robbery and are appealing for information and witnesses.
Detective Sergeant Alex Wild said: "We are urging the public to look at the CCTV and see if you recognise any of the offenders.
"We believe they are local and may well have been in the shop previously.
"If you know anything about who was involved or remember seeing a group of teens in the area around the time of the robbery we would be keen to hear from you."
Anyone with information should call police on 0161 856 3544 or the independent charity Crimestoppers, anonymously, on 0800 555 111.
