I seem to be having trouble getting the Magellan achievement, but I see a LOT that still have 0% on the global statistics for the game. Does anyone know if some of the achievements are bugged, or if it's just that the instructions are esoteric and unclear in their descriptions?!
The good money is on the achievements being either bugged, have not been "activated" for earning, or something else entirely.
At any rate, they are currently un-earnable, though if the patch last week fixed them, all bets are off (and there's some evidence that it did, see comment below).
I just won my first Victory with Harald of Denmark. No achievement.
My berserkers are currently headed towards Firaxis.
Also, I won on a huge map, by taking out everyone else... apart from the ones that died to others (like poor Gandhi who spawned next to the nice and peaceful Alexander the Great). I have a lot of heavily upgraded and very experienced berserkers...
Note: I specifically sent a ski infantry to get the biathlon one, worked right fine, a few turns before winning. So the achievement functionality is just fine, it's only working... not always.
Conclusion: two years later, the game is still buggy on achievements :D