Atlas Fallen: Deck13 gives us an overview of gameplay
You can find it below, accompanied by the official description of the developers:
In a devastated and sand-covered world, you must seize the divine power of a mysterious Gauntlet and wield heroic skills to defeat a tyrannical and omnipotent god. Tame the sands into three powerful weapons and move through the air with incredible speed and agility. Choose an unstoppable duo of weapons to battle and use the deadliest combos in a continuous flow between them. The weapons grow larger as Momentum accumulates to unleash all the irrepressible power of the Gauntlet.
The 151 Essence Stones found in the world of Atlas grant a wide range of extra effects and abilities. Whether you prefer to play aggressively or with a mix of shields, debuffs and cures, you can combine the Essence Stones as you like to create your approach to combat.
These tools allow you to engage in intense combat against a large bestiary of Spectres. Adapt and play wisely against each opponent and further expand your possibilities for fighting with a friend in two-player online co-op. You can play together the entire campaign of the story, finding the most incredible synergies to defeat enemies with an increasingly impressive style.