Into The Depths Gameplay Overview: Build & Survive Below

Core Gameplay Loop: Dig, Build, Survive, Repeat

Into The Depths is a single-player colony simulation and strategy game that fuses traditional city-building with Roguelite progression. Your primary objective is to establish a thriving settlement deep underground, beginning from a small outpost and expanding into the darkest caverns. Each run starts with a procedurally generated map, ensuring that no two expeditions are identical. The core loop revolves around four key phases: exploration, resource gathering, base construction, and survival management. You must carefully balance the needs of your colonists—hunger, sanity, and safety—while pushing deeper into the unknown. Unlike many colony sims, Into The Depths introduces a "run-based" structure where death or failure sends you back to the surface, but you retain certain upgrades and knowledge, encouraging repeated attempts.

Exploration and the Underground World

The world of Into The Depths is a sprawling, multi-layered underground biome. You begin in the relatively safe "Shallow Caves" but must dig deeper through the "Gloom Tunnels," "Crystal Caverns," and eventually the "Abyssal Depths." Each layer presents unique environmental hazards, resources, and creatures. Exploration is not linear; you will encounter branching paths, hidden chambers filled with rare ore, and deadly chasms. Your colonists can be assigned to scout ahead, but this carries risk. The fog of war mechanic means you must actively explore to reveal valuable resource nodes or dangerous enemy lairs. Successfully mapping out a new area is crucial for long-term survival, as it allows you to plan your expansion and avoid ambushes. For a deeper dive into the map structure, check our Map Guide.

Base Building and Colony Management

At the heart of Into The Depths is your colony. You must construct a functional base that supports your growing population. This includes essential structures like barracks for sleeping, mess halls for eating, workshops for crafting, and storage rooms for materials. Building is grid-based but allows for verticality, as you can dig up or down to create multi-level bases. Resource management is critical: you need wood and stone for basic structures, but deeper metals and crystals for advanced technology. You must also manage your colonists' needs. Each colonist has a "Sanity" meter that depletes in the dark or after traumatic events. Placing torches, providing food variety, and building recreational rooms helps maintain morale. For beginners, we recommend reading our Beginner Guide for tips on efficient base layouts.

Roguelite Progression and Meta-Upgrades

What sets Into The Depths apart from standard colony sims is its Roguelite progression system. When your colony falls—whether due to a monster attack, starvation, or madness—you do not lose everything. You return to the surface hub, a persistent home base where you can spend "Depth Tokens" earned during your run. These tokens unlock permanent upgrades such as faster digging, stronger starting walls, or better initial gear. This meta-progression ensures that each run feels meaningful, as you gradually become more powerful. You can also unlock new colonist classes and starting equipment. This system is designed to make failure a learning experience rather than a setback. For more details on upgrades, see our Upgrades Guide.

Combat and Enemy Encounters

The depths are not empty. Hostile creatures, from giant cave spiders to crystalline golems, inhabit the underground. Combat is real-time and requires you to equip your colonists with weapons and armor. You can craft basic spears and bows early on, but later runs allow you to forge magical swords and firearms. Enemy encounters are not always avoidable; some rooms are guarded by powerful "Elite Enemies" that block access to vital resources. Tactical positioning is important—placing ranged units behind melee fighters, using narrow corridors to funnel enemies, and setting traps. If a colonist dies, they are gone for that run, but you can recruit new ones from passing travelers. Learn about the different threats in our Enemy Types guide.

Tips for Your First Expedition

Starting your first run can be daunting. Focus on securing a food source immediately—mushrooms are abundant in the Shallow Caves. Build a simple shelter before the first night cycle, as darkness attracts more aggressive creatures. Prioritize researching basic stonecutting to reinforce your walls. Do not dig too deep too fast; explore horizontally first to find a safe perimeter. Finally, always keep an extra torch in your inventory. For a comprehensive list of starting strategies, refer to our Beginner Tips article.