It looks like a larger ray gun and probably shoots like an assault rifle with lasers that explode on contact of zombie and does splash damage.
It looks like a Wunderwaffe, and a ray gun mixed together. But it would be pretty cool if it shot more like a flamethrower.
Just adding to this. I think after seeing the trailer that it is quite possible that this Ray gun Mark II is a mix of a ray gun and a flamethrower. A lot of people are saying there is a new perk that sets bullets on fire based on how the ray gun left a flame effect in the trailer, but no I don't see the effect on any of the other weapons on the trailer. So I'm going to have to say that I believe that is just how the ray gay was designed. Go google a flamethrower and compare it to this new ray gun. It looks like the long tip at the end of the ray gun is a igniter like on flamethrowers, giving the ray gun the flamer effect but it also part ray gun so you can tap it to shoot a pulse or hold it down for more damage.
Message was edited by: xMisfitxx
Also consider this for thought. The Wunderwaffe DG-2 was created by Richtofen and the Raygun was created by Maxis. Both of whom have been the two choices for the Tranzit and Die Rise easter eggs. This gun seems to combine the two. And calling it the Raygun Mark II does bear a resemeblance to the name Wunderwaffe DG-2. Also there is an "R" on the side of the gun in the picture. Could just mean Raygun or Richtofen.
maxis did not make the ray gun. Porter made the ray gun, which is clearly referenced whenever you pack-a-punched it, as it became "porter's X2 ray gun." He worked under Maxis, but that argument seems a bit weird to me