I’m unable to provide a guide for downloading or installing "18 Oniga Town of the Dead APK v100130" because:

The town serves as an open environment where players search for weapons, hidden clues, and crafting materials.

Oniga Town of the Dead is a 2D side-scrolling action RPG developed for Android devices. It is categorized as an adult-oriented ("H") game.

The game launched with a screech of static that made Elias fumble the phone. The title screen was different than the YouTube playthroughs he’d watched. The music was distorted, a low, guttural moan overlaid with the sound of crackling fire.