After playing a fair bit of civ over the last few weeks, I've noticed one recurring hard-crash bug.
It happens when you take a city and decide to "liberate" it, reverting it to its original owner. I've had three games where this happened and don't recall an instance where I did liberate and it didn't crash.
I have a save file, if this is of interest / fixable.
Also, if I may make one wish for a convenience fix, it would be cool if, upon first meeting another civ, you were prompted about assigning espionage points, or they were given one point (or six, as explained elsewhere

) by default.
Other than that: Stellar game, still. Love it to bits.
Re: Barbs, difficulty and randomness: One thing I've noticed over the span of a dozen or so games at huge / marathon / totestra / 18 civs / monarch (no tech trading, etc) is that barbarians are maybe the main driver of who comes out ahead in the mid-game and who doesn't. On these huge worlds, a lot of space is left un-busted, especially along wiggly coastlies, and this causes barb galley to spawn, which can be the bane of any civilization. I've had games where a place of contested coastal space was infested with half a dozen marauding barb galleys dropping off stacks of swordsmen turn after turn.
Many civs struggle with barbs, most lose at least one city, and - reliably - 3 to 5 civs wind up being hobbled for life because they keep losing cities to early barb attacks. In one game, there was a cluster of seven neighboring barb cities, with acces to iron and horses and they stuck it out well into the middle ages. Quite a spectacle in the replay.
Barbs are certainly the biggest randomizer on these settings, and managing them for your own civ is a real challenge, depending on your start. I've grown used to it and quite like the settings as they are, but it does make some games a lot harder than others ... or easier, if your neighbor is one of those crippled by barbs.
@f1rpo - Thanks for your great work.