Bulwark Sol Get the game
Painted key art: a human warship holds beside an eclipsed planet while a swarm of Choir ships closes in.

Starship tower defense · iPhone and iPad

Bulwark Sol

Humanity was the last to join a very old war. Now the Choir has reached Sol, and the only thing between it and home is your line.

Coming soon to theApp Store See the game

Free to play · optional in-app purchases · optional rewarded ads

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Fleet and upgrades

Build your line

Borrowed alien technology bolted onto stubborn human steel. Eight ships, each with three upgrade paths of five tiers. Each ship can take two of its paths, so you choose which two and how far to take them.

  • Nine kinds of Choir hostile, each needing a different answer. Shrouded ones need a sensor. Armoured ones need the right gun.
  • Pause, speed up to 3x, and sell or rebuild between waves.
  • A squat, armoured hull carrying lit cyan coil stacks.Arcwright
  • A square fortress hull with a glowing turret ring.Bastion
  • A broad hull with a cluster of six launch tubes at the bow.Howler
  • A fast, arrow-shaped hull with swept fins.Interdictor
  • A heavy wedge hull with raised armour fins.Ironside
  • A carrier hull with a long, lit flight deck.Kestrel Carrier
  • A rounded hull with twin open mount rings.Lantern
  • A long lance-shaped hull with a violet mount ring.Nullbeam

One Interdictor, refitted down different upgrade paths

  • The Interdictor fitted with a large ring-shaped sensor array.
  • The Interdictor fitted with a dark violet null ring.
  • The Interdictor fitted with a snare launcher.

Commanders

Sixteen Commanders

Each Commander brings an aura, an order you call in battle and a flag that one of your ships flies.

Rank them up with insignia from fixed sources: the story, star caches, the daily supply and the Credits exchange. Every Commander can be earned without paying.

A Commander in a dark flight helmet with a lit visor.
A Commander in armour and a clear helmet, the visor glowing with a cyan display.
A Commander in a sleek helmet with a mirrored visor.

Campaign

A campaign across the Solar System

40 missions from the Moon outward, told in five story chapters. Every mission has three difficulties and stars to earn on each.

Then take the war further: Freeplay, a Daily Sortie and the weekly Long Patrol.

The Moon and a distant small planet against deep space, the first stop on the campaign map.

Every day, every week

Something new to fight for

  • Freeplay

    Win a map and keep going as the waves climb.

  • Daily Sortie

    One mission with one twist, and a new one every day.

  • Long Patrol

    A six-leg route that changes every week. Your fleet and your hull carry from leg to leg.

  • Research

    Long-term upgrades that run on a real clock.

  • Alliances

    Team up with other players.

  • Honours Board

    Cosmetics you can earn but never buy.

Our promise

Fair by design

  • No loot boxes, no random rewards. Every pack tells you exactly what's inside before you buy it.
  • No surprises at the till. Every price is shown up front on the store screen, in your App Store currency, before Apple's payment sheet opens.
  • A spending limit you set. Choose a monthly limit in Settings. Lowering it takes effect at once; raising it waits.
  • Earned, not bought. Every Commander can be earned without paying, and Honours cosmetics can't be bought at all.
A sealed supply crate: packs show their contents before you buy.

The line is yours

Hold Sol.

Bulwark Sol is free to download and play on iPhone and iPad.

Coming soon to theApp Store

Optional in-app purchases (Gems and fixed-content packs), which you can turn off in Screen Time. Contains optional rewarded video ads. The Daily Sortie, Long Patrol and Alliances need an internet connection.