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Hell Magus
Game design document

Game design document

May 13, 2026

1. High‑level concept

Working title: Hell Magus

Genre: Single‑player, dark fantasy action RPG (isometric, Diablo‑like)

Core fantasy: You are a lone sorcerer descending beneath a cursed town into crypts, catacombs, and hellish depths, wielding forbidden magic to purge an ancient evil.

Elevator pitch: A grim, replayable, Diablo‑1‑style ARPG focused on a single flexible sorcerer class, fully random dungeons, and brutal combat, with a single town hub and a 10‑level descent themed as Crypt, Catacombs, and Hell.

2. Design pillars

  1. Replayable dark descent
    • One town hub, one main dungeon, fully random levels each run, encouraging multiple playthroughs with different builds.
  2. Single‑class, multi‑build sorcerer
    • Only one playable class (sorcerer/magus), but multiple viable builds via stats, spell schools, and magical equipment.
  3. Oppressive, 18+ atmosphere
    • Grim, gory, low‑res isometric visuals, ambient drones, and unsettling soundscape.
  4. Simple structure, deep optimization
    • Short, understandable structure (hub + 10 levels), but plenty of room to optimize builds and routes over multiple playthroughs.

3. Target experience

  • Platform: PC only.
  • Engine: Godot 4.x, 2D isometric using tilemaps and sprites.
  • Controls: Mouse for movement and targeting; keyboard hotkeys for spells and UI.
  • Session: 3–4 hours for a first complete run; shorter on subsequent runs.
  • Performance: Target 120 FPS at up to 2K resolution; no networking.

4. Core gameplay loop

  1. Start in the town hub as the sorcerer.
  2. Visit NPCs to buy gear, heal, and receive main‑line and a few side quests.
  3. Enter the dungeon from town and descend through fully random levels.
  4. Fight enemies, gain XP, collect gold, spells, and magical equipment.
  5. Spend level‑up stat points to refine build and adapt to drops.
  6. Periodically return to town to sell loot, restock potions, and progress quests.
  7. Reach and defeat key bosses on deeper levels, culminating in the final Hell boss.
  8. Finish the main quest line and unlock the option to replay with new builds.

5. Setting and tone

World

  • Town: A single, small, ruined settlement built around a cursed cathedral.
  • Dungeon:
    • Level 1–3: Crypt (stone tombs, sarcophagi, dim torchlight).
    • Level 4–7: Catacombs (narrow corridors, mass graves, blood altars).
    • Level 8–10: Hell (organic flesh architecture, lava, grotesque imagery).

Tone and rating

  • Tone: Grim, oppressive, bleak; focus on dread and unease rather than heroism.
  • Visual style: Pre‑rendered low‑res 2D sprites in an isometric view, inspired by late‑90s isometric games like Diablo.
  • Content: Gory deaths, disturbing enemy designs, occult rituals → aimed at 18+ audience.

6. Player character

Sorcerer (Magus)

  • Role: The only playable character; flexible caster who can lean into different spell schools and stat distributions.
  • Fantasy: Scholar of forbidden magic, channeling hellish powers and arcane knowledge.

Base stats

Classic quartet + derivatives:

  • Strength (STR): Affects physical damage, carry capacity (if used) and some magical weapon scaling.
  • Dexterity (DEX): Affects hit chance, dodge/avoidance, and some projectile spells.
  • Intelligence (INT): Main spell power stat; boosts spell damage and mana pool.
  • Vitality (VIT): Increases maximum health and resistances.

Derived:

  • Max HP (from VIT).
  • Max Mana (from INT).
  • Attack Power (mix of STR/INT depending on weapon).
  • Defense / Evasion (from DEX/VIT + gear).

Progression

  • Level ups:
    • Gain XP from kills and quests.
    • On level up: fixed HP/Mana gains and a pool of stat points to distribute freely.
  • Build variety:
    • INT‑heavy glass cannon caster.
    • STR/INT mix for battle‑mage style (using melee‑oriented magical weapons).
    • DEX‑leaning spell‑slinger focusing on mobility and projectiles.

7. Magic and spell system

Spell schools

Spells are organized into schools; schools matter mechanically (resistances, synergies):

  • Fire: High damage, burn over time, often area‑of‑effect; some enemies resist or are weak to fire.
  • Frost: Control and debuffs (slows, chills), lower raw damage but strong utility.
  • Arcane: Pure magical force; versatile, mixed damage, utility (e.g. teleports later).
  • Blood: Risk‑reward spells using health costs, life‑steal, curses.

General rules:

  • Spells can have tags (School, Target type, Shape) used by mechanics and items.
  • Enemies can have resistances/weaknesses by school (e.g. demons more resistant to fire, weaker to frost).

Spell count

  • MVP: 3 core spells (one per main role: single‑target nuke, AoE, control).
  • Full game: ~10 spells total (spread across schools, plus possibly general spells).

Example MVP spell trio (for design reference):

  • Arcane Bolt (single target, low cost, main filler).
  • Fire Nova (short‑range AoE blast with burn).
  • Frost Grasp (single‑target or small AoE slow/root).

8. Weapons, armor, and items

Magical weapons

  • All weapons are magical (no mundane gear).
  • Weapon types might include: wands, staves, orbs, spellbooks.
  • Each weapon can have:
    • Base stats (damage, attack speed, school alignment).
    • On‑hit procs (e.g. chance to cast a small fire blast).
    • On‑use abilities (e.g. charge attack that consumes mana or has a cooldown).

Armor

  • Cloth armor only, with visible sub‑types:
    • Robes (generalist).
    • Cloaks (mobility/evasion).
    • Ritual garments (glass cannon spell‑power focus).
  • Provide:
    • Defense, resistances, and school‑based bonuses (e.g. “+Fire Damage”, “+Blood spell life‑steal”).

Other items

  • Rings, amulets, belts for additional magical properties.
  • Potions:
    • Health potions (instant / over time).
    • Mana potions.

Item rarity

Even if simplified for MVP:

  • Normal → Magic → Rare → (Unique / Legendary) framework.
  • Higher rarity = more affixes, stronger effects, unusual on‑hit/on‑use abilities.

Economy

  • Single currency: gold.
  • Uses:
    • Buying weapons, armor, accessories, and potions from town vendors.
    • Possibly paying for healing or other services.

9. Enemies and bosses

Families

  • Undead: Skeletons, zombies, wraiths in Crypt/Catacombs.
  • Cultists: Human or near‑human foes, sometimes spellcasters.
  • Demons: Hell creatures in deeper levels.

Basics

  • Behaviors: Basic melee, basic ranged, simple kiting; no complex AI in v1.
  • Difficulty progression:
    • New enemy types with unique stat profiles and simple mechanics as you go deeper.
    • Stat scaling on deeper levels (more HP, more damage, faster).

Bosses

  • A few key bosses:
    • 1 miniboss in Crypt.
    • 1 major boss in Catacombs.
    • Final boss in Hell (Diablo‑like encounter).
  • Boss fights emphasize positioning and spell use rather than complex scripted phases.

10. Town hub and NPCs

Town functions

  • Shop:
    • Buy/sell magical weapons, cloth armor, accessories, potions.
  • Healer/Temple:
    • Heal HP and cure curses/debuffs.
  • Quest giver:
    • Provides main quest line and some small side quests.
  • Storage:
    • Stash for extra items between runs / visits.

Structure

  • Single town map (small but detailed), accessed at game start and between dungeon runs, similar to Tristram’s role in Diablo 1.

Dialogue and story

  • Dialogue: Short, atmospheric lines only; minimal branching.
  • Story: Linear main quest (descend and defeat the source of corruption) plus a few side quests for flavor and rewards.
  • Focus on mood and lore hints rather than deep character arcs.

11. Dungeon structure and DRLG

Layout

  • One continuous dungeon under the town:
    • Levels 1–3: Crypt.
    • Levels 4–7: Catacombs.
    • Levels 8–10: Hell.
  • Each level generated procedurally using DRLG‑style rules:
    • Room and corridor templates per theme.
    • Spawn tables for enemies and items per depth.
    • Special rooms (shrine rooms, sacrificial chambers, etc.) as set‑piece patterns.

Progression

  • Player always enters from town at level 1 for a new run.
  • Stairs/portals connect levels; reaching deeper levels increases difficulty and loot.
  • Most quests are optional; progression requires only finding and taking stairs down (and eventually defeating the final boss), echoing Diablo’s simple progression rules.

12. Death, saving, and difficulty

Death

  • Death ends the current attempt and returns to main menu.
  • Player can reload last manual save (town or dungeon) like Diablo 1’s save system.

Saving

  • Classic single‑save ARPG:
    • One save slot per character (single character anyway).
    • Player can save in town and in dungeon; loading restores state to that save.

Difficulty

  • Base game ships with one difficulty: Normal.
  • Replay value comes from different builds, DRLG variation, and self‑imposed challenges.

13. Systems out of scope for MVP

Deferred to post‑MVP:

  • Crafting, enchanting, item upgrading.
  • Talent trees beyond basic stat allocation.
  • Multiple difficulties (Nightmare/Hell equivalents).
  • Complex dialogue trees and branching storylines.
  • Advanced AI behaviors (summoners, resurrection, etc.).
  • Meta‑progression between runs.

14. Technical specification

  • Engine: Godot 4.6.x (GDScript).
  • Rendering:
    • 2D isometric; pre‑rendered 3D models to sprites, plus hand‑touched art.
    • Tilemaps for floor/walls; separate layers for props and occluders.
  • Input:
    • Mouse: click‑to‑move, click‑to‑target.
    • Keyboard: spell hotkeys (1–5), inventory, character sheet, menu.
  • Performance:
    • Target 120 FPS at up to 2K resolution on mid‑range hardware.
  • Networking:
    • None (no multiplayer).

15. Production and scope notes

  • Assets:
    • Mix of self‑made pre‑rendered models/sprites and some purchased or free licensed assets (music, SFX, or art packs where appropriate).
  • Priorities:
  1. Replayability (builds + DRLG).
  2. Atmosphere/visuals (dark, gory, oppressive).
  3. Story (simple but coherent).
  4. Systems depth (iterated over time).

16. MVP definition

MVP should deliver:

  • One sorcerer class with stat progression and 3 functional spells.
  • Full loop: town hub → random dungeon → final boss → ending → credits.
  • 10 levels across the three themes, even if early art is placeholder.
  • Core systems: movement, combat, spells, loot, inventory, basic quests, saving/loading, town functions.
  • Atmosphere sufficient to communicate the dark fantasy tone even with prototype assets.
Last updated on
MVP (prototype) concept