Check out the journal section:
There is plenty of information.
As far as I understand, Elemental will be some kind of "Fantasy Civilization". They are currently discussing the economy aspects and included the forum members in the talks (https://forums.elementalgame.com/352821).
We know, that players are supposed to be able to design their own units, spells, equipment, buildings and things like that. For this purpose, there will be a couple of distinct "sporelike" creation tools available. Players can decide which content they want to make publicly available. After a quality check, this will be downloadable for every player. Frogboy once stated, that technically it should be possible to create a "Settlers of Cattan" as computer game if you thus desire. Meaning, the tools will allow for you to create all kind of different settings.
The focus will be on the human race: there are 6 "normal human" civs and 6 "Fallen" ones (Modding will for sure create many more. However, due to programming time, the devs focus on just one race so far. This has a lot to do with the tools just mentioned. If you as a player, design a plate armor for a human soldier, you can't use the same armor for a bear race as the sizes simply won't fit. If there would be an additional fairy race, you'd have the same problem.).
Being a fantasy setting and leaning strongly towards "Masters of Magic" (although Stardock did not get the license from Atari) there will be plenty of spells included (more then 100. The tools allow to create any additional spell you like). Magical creatures will play a role, too. However, they will be rare and extremly powerfull (dragons!). Thus, unlike the Heroes of Might and Magic, you will have to rely on normal troops. Once you get access to a dragon, this will be a "one dragon army" by itself and deal with most soldiers.
Armies seem to get a touch from the total war series. Remember, however: We are talking about a TURN based strategy game.
The focus will be on single player with a basic story written by professional authors. There are going to be multiple winning conditions (take a look at Galactic Civilizations 2: I highly recommend it. There you can see, what Stardock is capable of doing with an AI. It is truelly amazing!). A Sandbox mode as well as a campaign setting has been announced.
There is going to be some multiplayer functionality to it.
One additional thing: In some ways, you will be able to play it a bit like an RPG. You have to decide for yourself, if you will be the king of your empire, or if you just stroll along in the world solving quests and exploring dungeons.
That's as far as my little brainstorming can come up for now. You see, this is a highly ambitious project. If it will just come a bit close to what it claims to be, than it will be one of the best games ever. Of course, high expectations can also mean a big fail... But if there is anyone who can pull this off, it is Stardock, I think.
In general, there is a lot of general statements with nearly no detail on the mechanics. You can't really expect anything else as the game is in the alpha stage and might enter public beta (for those who preordered) in July/August or perhaps later, depending how things are going along.
Hope, this helps.