GunPorn wrote a post on this very interesting shotgun. It is a reverse pump action bullpup shotgun invented by a South African company.

From what appears to be the official website.

Neostead Features

* Selectable twin tube magazine
* 13 shot capacity
* Overall length is 27 inches with full length barrel of 22.5 inches
* Totally ambidextrous as all controls are centrally mounted
* Pump action is reversed
* Straight line stock with magazines above barrel
* Negligible muzzle lift
* Intergral carry handle houses ghost ring sights
* High stength polymers for main external components
* Boltless design
* Sling swivels on top

Safety Features

* Trigger safety locks trigger positively
* Pump handle operates trigger disconnector
* Pump lock
* Firing pin positive return
* Out of battery firing prevention
* Reversed pump action

Wikipedia has this to say

The NeoStead 2000 (NS2000) is a type of shotgun developed by the South African company NeoStead. Along with the Pancor Jackhammer, it is considered one of the most technologically advanced shotguns ever created. The NS2000 has been used in trial runs for a few years by special forces like the British SAS and there are hopes at NeoStead that larger weapons manufacturers will license the production rights. Production of the shotgun began in 2001 and the first models were made available in October of that year.

The NS2000 is a 12-gauge pump action shotgun weighing in at just over 3kg, designed primarily for security and civil disturbance situations.

The firearm includes a 22.5 inch (572mm) barrel despite the overall weapon length of just 27 inches (686mm). The short length makes the weapon easier to handle in close quarter situations however, unlike most firearms of this type, it can still remain accurate at relatively long ranges. The long barrel length is achieved by using a bullpup configuration, with a rear-fed tubular magazine.

Another aspect of the NS2000 is its dual six round magazines. The selector switch can be set to left, right, or alternating. For example in riot conditions less-lethal flexible baton rounds can be used with standard rounds in reserve.

A possible production variant of the NS2000 has an 18 inch barrel in a weapon with an overall length of 22 inches. The shorter length reduced the magazine capacity to 5+5 rounds and makes the weapon easier to import or license in many countries.

Its pump mechanism operates in a forward-back motion, due to its rear-load configuration. This is different from conventional pump methods as the pump action is achieved by shifting the hand forward-back, as opposed to the standard back-forward motion of the non-trigger hand.

Some more photos

This photo makes it look a bit like a side by side shotgun. The two cylinders next to each other on the top are the magazines.

Patent application drawings:

This shows how the magazines are inserted: