There's a reward at zone 100.

400 gold!!!!
Random facts:
-your hacks actually do expire after being used for 99 zones.
-Angela's buffs/damage gets crazy with Odin's synergy at zone 100. I had extremely bad luck with my hacks, but I still continued because it was just sector 1. I was able to hit 4 million damage fairly easy on specials.
-the extra opponent increase on each level gets lower, going from 5% all the way down to a 2% increase in each zone
-at high levels, Angela can very easily heal up to 100%. With suicides, or by tanking an attack, her regen gets her up to 100%.
-i could take a five combo hit and not die. I'm assuming it had to do with Angela's armor buff increasing by 15% each zone, but the opponents difficulty only increasing by 2%
-does sector 2-6 have a better, hidden reward at zone 100?
-the bosses don't rotate between overseer and shocker once you're past zone 24
-there are NO revives or heals outside of zone 25