Merge Dungeon is an arcade dungeon crawler built around merging. Your soldiers need to fight their way out of a dungeon packed with monsters, and the only way to keep up as the monsters grow stronger is to upgrade your warriors' equipment.
The game follows a simple loop: fight, upgrade, merge, repeat. Monsters come at your soldiers, and you need to defeat them all. Between battles, merge matching pieces of equipment to create stronger versions, and use upgrades to make your warriors tougher. When a boss appears, wait until you are ready before you attack, because bosses hit much harder than ordinary monsters.