Almost kills all the three. Each is rescued by one another. Takes an assault rifle round seemingly straight through the heart. Black Manta mentions that they should leave before Slade gets back up
Kills 300 henchmen fairly quickly. Detonates an explosion on his position that kills the remaining henchmen but not him. He lifts a large rock to escape the rubble.
Somewhat depowered and thrown off by the use of his second eye. Seemingly takes the upperhand, but then is attacked by Harley. Then hurts Bruce, but the fight is interrupted when Harley destroys the building with explosives. Stalemate.
Basically Slade releases an evil God on her island and she kicks his ass for it. Although Slade wasn't necessarily fighting back. He hits her once and makes her bleed. His healing factor/durability holds up well against her attacks. Eventually she knocks him tf out.
And maybe do the same thing as reddit... that is, make the separate threads for the classic, DCnU and Rebirth versions. But that's up to you, of course.