Due to the Roaster's short range, placing it on one side of the Builder Hall cannot prevent Sneaky Archers and Beta Minions from destroying the Builder Hall from the other side.
The Roaster can destroy swarms of Raged Barbarians that are coming into your base from a distance.
The Roaster can keep the Skeletons from the Drop Ship at bay, giving time for other defenses to take them out.
Try to put units with a lot of hitpoints in front of support units with less hitpoints to distract it from shooting the support units. The Battle Machine works great.
Try to scatter the troops so it doesn't hit every troop at once.
The Roaster undergoes significant visual changes at all levels, particularly levels 3 and 8.
At level 1, the Roaster appears as a teapot-shaped heptagonal metal vessel held together by wooden plates and rope. The spout is glowing red and has fire emerging from it.
At level 2, the ropes are replaced by additional planks on the base.
At level 3, most of the wood disappears and is replaced by wooden scaffolding, and the base's orange paint becomes visible. A heptagonal bolt is also added at the top.
At level 4, the base's paint becomes red and a wooden ladder is added.
At level 5, all of the wood disappears, a stone base is added to the vessel and the bolt at the top turns golden.
At level 6, the stone base gains another layer and the ladder becomes metal.
At level 7, the top layer of stones is replaced by golden band, the ladder turns gold and the muzzle flattens a bit.
At level 8, the ladder is gone, the golden rim is shorter and there are two pipes leading to the vessel. A timer also appears on the bottom of the Roaster, similar to the timers on the level 1-4 Mine and Mega Mine.
The Roaster was added on 6/27/2017.
The Roaster seems to have parts of its "scaffolding" removed with each of its levels, and then more stuff gets added on.
Tapping this icon displays information about the Roaster, such as Level, Damage Per Second, Hitpoints, Range, Damage Type and Targets.
Tapping this icon begins upgrading the Roaster to the next level, if you have enough resources and a free Master Builder or O.T.T.O. When the Roaster is at maximum level, this icon is not shown.
Tapping this icon instantly upgrades the Roaster to the next level, at the cost of one Hammer of Building if you have one. When the Roaster is at maximum level, this icon is not shown.
Tapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of the displayed number of Gems.
Tapping this icon, which is displayed only while an upgrade is in progress, instantly finishes that upgrade at the cost of one Book of Building. This icon is only shown if you have at least one Book of Building.