I realize that Slade when written can go up against, and has weapons that can take out Kryptonians. I know he has a healing factor (I'm not convinced it's on the level of Logan's though). Due to it being written though, it's not likely for him to pull wins against that calibre of opposition. He gets the Batman treatment alot, mostly due to him having showings of besting Batman. Regardless, in a non PIS situation, I don't see how he's getting past the two advantages I posted previously, plus his armor, healing factor (on par with Logan's), tendrils made of carbonadium, superhuman strength (that he's able to amp through the life), and enhanced senses (this one I'm not 100% on, I'm pretty sure their enhanced though, since Romulus was trying to recruit him also). PIS involved I could see this being an even split, with Slade taking a slight majority. Otherwise, I see Slade dying very horribly.