Lub-dub.

As you fight your way trough the hordes of nightmares born from your own imagination, the pulsation in your ears grows stronger.

Lub-dub. Lub-dub. Lub-dub.

And not just in your ears. You're starting to feel the tremors in members. Your arms. Your legs. They're shaking in unison with the walls, with the floor.

Lub-dub. Lub-dub. Lub-dub. Lub-dub. Lub-dub.

As you get closer to the centre of the perilious labyrinth of flesh, you notice that the small changes in palpitations have synced both your own heartbeat and the tremble of the rooms. It is as if your own heart was shaking the whole Earth with each and every beat like a thunderous war drum, preparing you for the battle ahead.

You continued onward as the heartbeat grew more and more deafening with every step, until you finally arrived. Giant black doors, arches adorned with a pair of fearsome skulls. And behind them — The Heart of all your troubles.