The main focus in CoE3 is that each race plays differently. We're not talking about a unique building and unique unit, we're talking about completely differently, with different mechanics and different goals. Perhaps you're playing a druid, focused on amassing a vast forest and jungle empire from which to harvest ingredients to summon creatures of the woods with no practical need to conquer mines or even towns! Perhaps you're a dwarf, who's only concern are mines and produce units at a set rate every turn and focus almost entirely on upgrading those units to survive as long as possible, since they are so difficult to replace. With 18 different factions that alone is enough to keep your play dynamic as you vie for control of the map to conquer Elysium. That isn't where it ends, however, there are 6 scenarios in which your game takes place that will help randomize the map. These scenarios range from a the early days of an agrarian world to a giant conquerable gleaming capital, to a fallen empire filled with the living dead and scarred by battlefields and tombs. There are also random events to contend with, from merchants to the very gates of the underworld opening portals to your realm, your hands will be full before you even make contact with the enemy.
In each game the objective is to defeat your enemies by relying on the strengths of your chosen race. Combat in CoE3 is automatic to keep things streamlined, but that doesn't make it non-strategic. Each unit has a desired "location" it wants to be in the battlefield. Archers want to be in the rear, heavy infantry want to be in front. As you can imagine, putting together an army that has enough strength to protect the powerful archers and spell casters in the rear is vital. It goes beyond that though, as you must determine your enemy's strengths and hopefully be able to counter their strategy. An army of a mere 10 trolls is extremely dangerous, perhaps able to bring down a dragon, but they can only kill 10 creatures at once. An army of 50 small units will make short work of your trolls. However, an army with a wizard able to cast high level spell may completely destroy all 50 small units in one shot but would be unable to harm 10 trolls. Determining the strength and composition of an enemy army is a vital skill, and since hitting in combat, damage, and even the very spells that will be cast are randomized based on the abilities of each unit, every battle invites potential disaster and a change of plans.
For more information on the game, check out the official Conquest of Elysium 3 website.