Hammerfight is a 2D fighting game between hovering machines equipped with different kinds of blunt weaponry. The game is set in a world above an abyss where three houses rule: Kadish, Kelete and Gaiar. They all manage to locate broken machinery and turn it into flying vehicles. Although they are at peace at first, a bloodthirsty brother quickly turns it into a real war. The player controls Gaiar, a young trainee who quickly works his way up.

In Solo - Warrior's Path, one of the game modes, players are introduced to the story and take on various missions controlling a flying vehicle. It is fitted with a swinging, piercing object. In order to attack, the mouse needs to be moved around in circles to build up the swing, and then attacking is done by smashing the weapon into enemies, with physics influencing the speed relative to the player's movement. Various missions are introduced through cutscenes. The player often will need to work together to defend outposts, or ward off large enemies or swarms of small creatures. Some missions also take place in tournaments or settings where the player's vehicle is held fixed through a chain.

Starting with a small and fairly feeble weapon at first, better maces and swords can be found. Players can choose to switch between weapons, weld them together, or add gunnery through an Arquebus or bombs in the armory. The main game modes contains branching paths and there are also three additional modes to unlock: Hall (a training mode), Grim (a patrolling/survival mode) and Hammerball.