"This cannon delivers a fierce gunpowder blast, damaging enemy troops near where the cannonball lands. Invaders will fall like autumn leaves."
The cannon tower has a wide range similar to archer towers, though it fires at a relatively low rate of speed and deals splash damage. It can be unlocked by playing the campaign. By collecting a full set of defensive Loot bonuses you can gain access to Cannon of Doom which will give you an extra cannon for two days. Cannons can't attack enemies within 1 radius.
Attacking a base with high level cannons is tough. Either try to kill them ASAP or try to avoid them, if using a basic unit army (e.g. samurai, archer, ninja). If using a basic army, knowing the number of hits to kill your units is key. Secondly if forced to battle a cannon, spread your troops and try to avoid funnel points. If possible, distract cannons with units across the base where splash will not affect your main army. Always try to pick off defenseless cannons as cannons can not attack troops that are too close to itself. Since cannons do mainly splash damage, healers are especially effective against them, and especially effective against Poison shot.
Cannons have a long range, so it's best to keep them towards the center of your base to protect as much as possible. Since cannons have a slow shot, it's best to place them where units will need to pause to destroy walls or other buildings first to ensure the cannonball hits. Freeze shot and Poison shot are both good to use, though if you use Poison shot, it is better to spread out your cannons since poison does not stack.
"Freeze Chance - As well as dealing damage, these cannonballs have a chance to freeze the enemy to the spot."
Cannons have three options for a weapon. The stats for the Standard Shot are in the above "Stats" table. The other weapon is Ice Shot, which do 10% less than normal damage than the Standard Shot, but have a chance to freeze the targets for 2 seconds. Ice shot cannons are marked by white snowflake markings on a blue flag.
"Poison targets in an area effect, doing damage over time."
Cannons have three options for a weapon. The stats for the Standard Shot are in the above "Stats" table. Poison shot greatly reduces physical damage per second by reducing the physical damage and increasing time between attacks, but greatly increases total damage in the form of poison. This is very dangerous at high levels and a single healer can barely keep units alive through the poison. The weapon variation can be purchased in the Onyx Market for a one time fee of 4900 Onyx, which will enable the weapon choice. Poison shot cannons are marked by green skull markings on a purple flag.