For a game released after 2015 it is really well balanced game. What is most amazing is that the developers have kept many of the base concept from the original FG game. The only thing I dislike is the heavy graphics and short campaign. I have always thought that this types of games need a clear 2D graphic with some beautiful sprites, where we can plan our strategy in a most focused way. For example, I did not take the dragon mount from the Dragon Island, because it was too annoying, weaving those mighty big wings over my screen. Some times I had to bend my head aside to look for the unit under the dragon :). Other from that, there are some minor things that are bearable or fixable, compared with the original game.
Story. The story of FG2 take place on one continent. Again, some missions will lock others so we can take different paths. We lead a noble barbarian tribe against the corrupted empire to save the world. Also the mission turn limit now only affects the spoils we get from the mission and is not a loose mission timer.
Experience. In the original FG, the unit with the final blow takes all the all experience. In FG2 all units 3 hex away from the target gets the experience. Except if a unit 4-5 hex away makes the final blow - it also get the XP.
Units. There are 4 main types of units, though they have very different race varieties, like human archers or centaur archers. The upgrade tree is more like Heroes style and we use 3 main resources to upgrade our unis in the path we choose. I just miss the concept about not knowing what is next unit upgrade from FG. One motivation was to reach all units max upgrade and see what is it :)
Items. Items are endless, not like in FG1. There are also rare(purple) items that make which of which more wonderous things. Heroes can carry 3 items and most single entity units can carrry 2 items.
Ruins. There are 5 types of ruins. The real ruins, caves, camps and settlements. The ruins and settlements may drop rare items. The caves I farm for boots (Water walking boots are so so so needed). The camps may drop some mana or health potion. But what is most not good is that there is no some type of shop to sell the unnecessary items at least. I believe this should be considered.
Terrain. Like the loading screens says, the terrain is a major part of the game. There are deep water, where only lizards can go, water, plains, roads, rough, woods and mountains.
Resources. Beside the 3 main resources to upgrade our units, there is an interesting concept with mana nodes on some maps where we get mana to cast spells and summon creatures.