Level Halt is bugged. THe first enemy killed stays in mid-air, and the other enemies do not arrive at the screen. Moreover, the abilities text stays on the screen.
Update: after a few turns, my food production went to minus. My gatherers produce -1.2 food, and my hunters -1.6 food per turn. Note, I did surrender to barbarians several times.
Update, after a few more turns, my production is set to 0 - gatherers and hunters produce 0 food per turn. This happened after I joined with some nomads. I got 2 people, but fully lost food production.
I am now playing my third time on chieftain and at some point of time a strange thing happens: without announcing an ice age, my food production goes down. This happens for a few turns in a row, destroying the food production fully. For example, my hunters, with trapping researched, produce 0.8 food per turn per hunter. This should be around 4 food per turn, so it seems this was like I had 3 ice ages, stacked.
This happens now third game in a row.