Potential interest here, but a few things:

It seems like you have some interesting ideas, but the way it's presented kind of makes me think this might be more suited as a Free RP rather than Casual level. I understand if you're holding back some information because you don't want to put a lot of work into something and then not get a lot of people interested, but I think more info might entice people more. For instance, what's the setting like--you included the Post-Apoc tab, so is the world in a state like Fallout? Or an endless barren desert? Or just slightly worse than modern day, with cities abandoned or destroyed because of the monsters? Do the people live in walled or domed cities to keep the monsters at bay, or do they scrounge to eke out a living anywhere they can in the midst of a new, harsher environment akin to pioneers? Obviously the Sors Cells have produced some biomechanical things, but other than that what's the technology like? Is this a setting where humanity has had to restart, pushing it back to medieval stages, or is this a far flung future where everything's chrome and has Tron-lines running everywhere? 

Also, I can definitely see the God Eater influence in the sword/gun weapons, but might I suggest making it so that the weapons can have other forms besides just swords and guns? That seems like it would make it much more appealing, because people love to have weapons, fighting styles, etc that make their characters stand out more. 

And finally (sorry if I'm rambling), maybe you could elaborate on the goal? Obviously the players are part of this Cerberus organization that hunts the monsters to protect people, but are they mercenaries who only do the work they're paid for, or are they like government service or a military that hunts monsters no matter where they appear? Do they assign squads, the entire force, or individuals to handle different situations? Is their goal simply to protect people, or to exterminate the Sortis once and for all? And what else, besides slaying Sortis, are they doing to try and accomplish those goals? Do the slayers bring back pieces of the monsters to study, or to use Monster Hunter style to make equipment? Are there any antagonistic or competing organizations that oppose Cerberus?

I hope these walls of text haven't discouraged you, but I see some definite potential in this idea, and I just thought I'd offer some advice.