Games Like Active Immunity

Something has slipped past the skin. You are what the body sends back. Active Immunity is a twin-stick bullet-hell roguelite fought inside the human body. Pick an immune cell, drop into infected tissue, and hold the line through 25 escalating waves of bacteria, viruses, fungi, parasites and worse. Weave through dense bullet patterns, stack upgrades into a build that feels unfair, and when the campaign is cleared, find out how long you last in endless.

Every cell has its own fire pattern, stats and special ability. Start as the Natural Killer Cell, and take each cell to wave 10 to unlock the next.

Every level-up is a choice. Draw from 54 upgrades across five rarities, from Common to Legendary, and max one out to unlock its evolution - 11 in all. Put the right pieces together and one of 23 synergies kicks in, turning a decent build into a screen-clearing one.

Eight pathogen families each fill the screen their own way: viruses that teleport and fire aimed spreads, fungi that release spores, tumours that split when they die, prions that spiral and shatter. Bosses arrive on waves 5, 10, 15, 20 and 25 - eleven of them, from the Viral Hydra to the Prion Cathedral, each with its own health phases and bullet patterns. Before key waves, you choose how the outbreak mutates. Every choice is permanent and stacks, so each run gets harder in a direction you picked. Add run modifiers, encounter remixes and permanent contracts when you want more risk for more reward.

Bring up to three friends into an online co-op run through Steam. Experience is shared, but every player levels up and picks upgrades on their own, and the outbreak scales with the size of your team. Make the fight your own with the Steam Workshop: new enemies, cells, bosses, bullet patterns, upgrades and sounds. Modded runs keep their own progression, so your official save stays clean.