Worms Forts: Under Siege is a turn-based strategy game in which two to four players compete against a team of four worms using weaponry and forts. Each player takes turns bombing, shooting, inflicting natural and unnatural disasters, punching, and blowing up the opponent’s worms in a timed fashion. Each worm has a fixed amount of health, and when that health is drained or drowns, the worm dies.
The franchise’s ability to construct facilities to aid in the fight is new. Construct hospitals to resurrect dead worms, science labs to boost your firepower, strongholds to base your operations and protect your worms, towers, keeps, castles, and citadels from deploying weapons from their tops, and weapon factories to produce multiple weapons around them at the start of each turn. Along with these standard structures, you can construct Wonders, which your opponent has two turns to bring down; if they fail, you win. If they build their own, you must destroy it to win the game.
Along with the standard Worms-style weapons such as the minigun, bazooka, rocket launcher, earthquake, and homing pigeon (a homing missile in the shape of a pigeon), you will also have weapons to destroy buildings such as the trebuchet, fridge launcher, nuclear strike, and Trojan Donkey (which you can place wherever you want and it will remain there until it explodes; the time it takes to explode is unknown). Some weapons, such as the Old Women and Rhino, can be directed to a specific place and then exploded on contact, or they can be exploded early by pushing a button.
Various boxes will fall from the sky or teleport onto the playing area throughout the game. Crates are classified into four types: weapon crates (more powerful weapons); health crates (increase the health of a wounded or sick worm); utility crates, which contain instant utilities such as spy (see the contents of all boxes on the field), double time (doubling the time for your turn), and double damage (inflict double the damage for one turn); and collectible utilities such as freeze (freeze your worms or buildings to protect them from damage for one turn), parish.
Single-player mode allows for a quick game, tutorial, campaign, trials (death matches against the CPU), and the viewing gallery, which will enable you to view movies you’ve unlocked in the game by winning matches, see how much of the game you’ve completed, check the credits, and browse the Fortapedia (a list of buildings available in the game and their descriptions).
As with the other Worms games, there are numerous options for setting up a multiplayer match against other players, including letting the CPU play. Choose schemes (the type of playing field – Roman, Egyptian, Samurai, and Old World), landscapes (the kind of playing field – Roman, Egyptian, Samurai, and Old World), Fortpot (a slot machine that randomly selects three game options from the many available), game settings (wins required, turn time, and so on), worm health and sudden death settings.
