There are 3 different kinds of super weapons in Strike Tactics.

The Disruptor Cannon 

An extremely long range artillery unit with massive firepower.

The Ion Cannon

More firepower than the disruptor, but at a much closer range. The Ion Cannon is also highly mobile as you can see in the first few seconds of the game trailer.

The radial gun

An area-denial unit which is stationary, but shoots a fury of cannonballs in all directions if an enemy unit approaches. I'm debating wether these cannon balls will be aimed by the gun, or if their destinations are completely random. The radial gun will be able to effectively deny both air and ground units in something like a 1,500 pixel radius.