How things will go from here..
Okay. This is my theory of how things will be going from here on.
The next Gantz mission will start. Either it's going to be against the vampires or the vamps will interfere. Either way, the Gantzers will end up fighting the vampires.
The reporter from 227 will find out that this is happening, and will phone Kurono - as 227 ended with him asking for Kurono's number. Kurono will rush down to where the fighting is happening, hoping to get the answers to his amnesia. Naturally Kurono will be recognised by both parties and be drawn into the confrontation.
In order to protect himself, Kurono will pick up a gun from a fallen Gantzer, or be given one by one of the others. He'll be scared, and hiding from the vampires, until a group of them find him. Then Kurono will raise the gun, shaking, and pull the trigger. Nothing will happen. Then Kurono, in a confident voice, will say "The top trigger is for locking on..."
Kurono will then have all his memories back, and in true Kurono fashion will exterminate all of the vampires trying to kill him. Then he'll be faced with one of the Vampire bosses, probably the blonde guy we see in 228. And even though he'll fight back admirably, Kurono will lose, and he will die.
After seeing that, the Gantzers will lose hope, and will start to lose their battle too. Except when it seems like everything is over, a Gantz teleport beam will start, and it'll be Kurono, wearing a suit and carrying weapons.