Hero Siege is fast paced and sometimes chaotic. Twin stick controls handle character movements and attacks with hotkeys or onscreen buttons for character cooldowns, potions, or usuable items.
Action is broken up into waves of enemies. After all enemies in a wave are cleared a countdown to the next wave begins or the player can then summon the next wave immediately. The number of waves between boss battles are determined by the selected difficulty. After each boss battle the player can then proceed to the next arena. Each of the game's four acts consist of five such arenas.
In addition to arenas there is a random chance of a locked dungeon entrance spawning when a wave is summoned. After the wave is cleared the entrance to the dungeon will unlock. Dungeons generally feature traps, enemies, block and button puzzles, and a boss fight before returning the player to the arena to continue clearing waves.