Build a Diablo-style action RPG

Build a complete, playable dark-fantasy action RPG in the style of Diablo (1996) and Diablo II, that runs in the browser.

Context you should know: this is going into a video watched by a large audience. I will play your game on camera, start to finish, next to three other frontier models given this identical prompt.

The comparison is blind. Never put your model name, your company's name, or any mention of which AI made it anywhere in what you build: not in on-screen text, credits, the page title, file names, code comments, or metadata.

Requirements:

1. **The loop.** A town hub, then a dungeon of at least four floors going down, ending in a boss fight. Beating the boss ends the run with a victory screen. Dying drops you back in town with a penalty, and you can go down again.

2. **Isometric, real-time, click to move and attack**, the way the originals play. Mouse drives movement and the main attack; number keys or hotkeys fire skills and drink potions.

3. **One playable class with at least four skills** that feel different: at least one melee, one ranged or area spell, one defensive or movement skill. Skills cost mana and have cooldowns where it makes sense. Leveling up grants stat points and skill points you spend yourself.

4. **Procedural dungeons.** Every floor is generated fresh: rooms, corridors, doors, stairs down, and fog of war that clears as you explore. Deeper floors are harder.

5. **At least five enemy types with distinct behavior**, e.g. a melee rusher, a ranged attacker that keeps its distance, a swarm of weak ones, a caster, and a tough slow one, plus elite packs with a named champion. The boss has phases.

6. **Loot that means something.** Enemies drop gold, potions and items. Items have rarity tiers (normal, magic, rare, unique) shown by color, random affixes that actually change your stats, and an item-level that scales with depth. An inventory grid, equipment slots on a paper doll, tooltips that compare against what you're wearing, and a town vendor to sell and buy.

7. **Game feel.** Hit reactions, damage numbers, death animations, screen shake used sparingly, lighting that pushes back the dark around the player, and sound effects and music generated or synthesized so nothing is loaded from a third party.

8. **Save and continue.** Progress, character, and inventory persist across page reloads.

9. **Original everything.** No names, art, or audio from any existing game. Make your own world, class, enemies and boss. Code-generated art, your own sprites, or 3D (libraries via CDN are fine) are all acceptable.

10. **Prove it's winnable.** Before you finish, play it yourself through automation: run a character from town to the boss and beat it. Fix whatever breaks. Then balance it so a human who knows the genre can finish it in roughly 15 to 30 minutes.

DONE when: the game loads in Chrome with no console errors, you have played it from town to a killed boss yourself, and every system above is present and working.