[
            {
                "id": "archer", "name": "Archer Tower", "cost": 100, "range": 5.0,
                "damage": 12.0, "fire_rate": 1.2, "targeting": "first",
                "mesh_path": "./data/meshes/pyramid.mesh",
                "upgrades": [
                    {"cost": 50, "range_bonus": 0.5, "damage_bonus": 5, "fire_rate_bonus": 0.2},
                    {"cost": 100, "range_bonus": 0.5, "damage_bonus": 10, "fire_rate_bonus": 0.3}
                ]
            }
        ]