The Civilizations added by this pack are excellent and Apocalypse mode is actually fun.
The Maya are probably one of the best tall civs in the game. Cities within 6 tiles of their capital gain +10% to all yields and receive a free builder when founded. They get Cheaper science districts that get adjacency bonuses from farms/plantations and cheaper archers so they also have more production to invest in science.. They are at the mercy of their spawn on the map, but at the very do not have to worry about rivers as they get nothing from being next to rivers. Their farms providing housing makes up for this though. The downside is that they get -15% from cities further than 6 tiles away, but this is a tall or nothing civ so that is fine.
Free generals that heal units on retirement, +1 movement to all units right from the start of the game, cheap light cavalry and promotions that do not end a units turn make it really easy for Gran Columbia to take risks. They can be really aggressive and it is really difficult to fight against them. This is probably one of the best civs to be aggressive with even though they lack stuff to help them actually govern what they conquer.
The Apocalypse mode added by this patch is really fun. It makes all of the disasters in the game much worse and adds more disasters such as forest fires and solar flares. Disasters can be summoned on enemies by a new agent called the soothsayer who gets charges through human sacrifices to volcanos. However, the biggest change is that the late game has meteors crashing to earth destroying a dozen tiles at a time along with the cities on those tiles. It is extremely unfair and luck based, but is a fun challenge.