This guide from Destructoid explains how to reach and defeat the brain, the final boss unlocking the true ending in the parasite-themed game Pathogenic. Players controlling the parasite must fight through six body regions in sequence, each concealing a hidden "sigil room" containing a key needed to solve the brain's access puzzle, making this one of the game's most involved challenges.

To progress, players must clear the skin, intestine, stomach, liver, lungs and heart, collecting a special organelle and puzzle keys along the way, then unlock sigil rooms using a specific arrow-key sequence (right, up, down, up, left, right). Defeating the heart's boss triggers an endless mode granting access to the brain, where players must use their collected keys to complete a randomised shape puzzle within three attempts, all in a single unbroken run, as death or failure means starting over.