Remix: IdleWorlds

Build a small, playable browser game inspired by "IdleWorlds" (RPG).
Concept: An old-school text-based MMORPG where your character keeps progressing even offline, with rare loot and a fully player-driven economy—all playable for free in your browser.
Tone/hook (from the game's own page): IdleWorlds is a long-term browser MMO idle RPG where you fight, mine, smith, brew potions, trade on the market, and keep progressing for weeks.
Tech: use plain HTML, CSS and JavaScript (or a lightweight engine you know); keep it to a single page that loads instantly with no login or install.
Controls: keyboard and mouse on desktop, shown on a short how-to-play screen.
Multiplayer: the original is listed as multiplayer. Start with a local or bot opponent, then add online play (e.g. WebSockets) once the core loop is fun.
Core loop: include progress saved in localStorage.
Steps: 1) get the core mechanic playable with placeholder shapes, 2) add win/lose conditions and restart, 3) polish feel, visuals and sound, 4) add your own twist (setting, character or one new rule).
Make it your own: don't copy the original's name, art, text or code.