Its already been established that there are other GantZ teams and they are in some form of competition, and taking notes from Oku's Zero One manga, i feel that its more than likely that the GantZ teams will be facing one another sooner than later if not in direct combat, then in a point-wise fashion. Maybe the losing team will be deleted or something. Beating the strongest boss in GantZ to quote one of the vampires, I'm sure opened up a door to a much larger and broader array of missions.
Some predictions I have are:
a) Someone will almost get 100 pts to revive Kei but will be "sabotaged", perhaps by Nishi.
b) Nishi will be the direct or indirect cause of death for several GantZ members and may even sell out to another "team"
c) Kato will get it on with Kishimoto
d) Kato's little brother won't ever get into GantZ
e) Whenever it ends, it will be dissappointing but acceptable
f) a new weapon will be introduced shortly, perhaps in the form of the ultimate weapon, but from the standpoint of another team, since our main team lost Izumi. Perhaps our GantZ team will have to face another GantZ team that makes use of the ultimate weapon.
g) the remaining vampire boss that got into the GantZ room will make a startling revelation about GantZ in the next chapter!