Why would there be a sequel? It's based on a light novel they butchered, they already implemented all the content of the light novel while changing almost all of it, there's no more original content.
It's not a bad film, I just hate that it was somewhat advertised as the adaptation of "all you need is kill" and as decent of a movie as it is, it's a piss poor adaptation.
I'm just coming at this as someone who didn't even know it was based off a book and thought the universe and concept was cool enough to warrant more content.
Yeah it was billed as some Tom Cruise slock like it was some video game movie. Heavy on the cgi but pretty good far as near future sci-fi goes especially with time travel.