[Spoilers] Old Harry's Game

[NobleHelium]

I think next turn will be interesting. Serdoa has 20 Horse Archers, a spear, an archer and five catapults. Hydra has seven spears, 17 knights, three axes, seven crossbows and an unattached great general. The turn goes to Hydra next, so Serdoa doesn't have any time to react to these... Also, why is serdoa farming that plains hill?

Hills cannot be farmed. Your arrow is pointing at the wrong place. That grass hill only has one horse archer on it and no other units, because there's only one white dot at the top of the banner. It looks like the tile being farmed is NW of that, the flat grassland with the horse archer facing the southeast.

Finally, how come Azza doesn't own the tile marked 50% - it was 50% a couple of turns ago but now I've got 43% culture to his 56% - why doesn't he control it? Something to do with him paying tribute since the end of our 1-turn war?

Tiles generally only change hands due to cultural majority at full EOT. Otherwise tiles near 50% culture would constantly flip as each player ends turn and puts his culture production into the tile.