Back to browse
An Interactive Guide for Castlevania II: Simon's Quest

An Interactive Guide for Castlevania II: Simon's Quest

by baclap·Jul 14, 2026·2 points·1 comment

AI Analysis

●●●BangerWizardryRabbit HoleCozy

Extracts sprites and audio directly from ROM binary at runtime instead of static images.

Strengths
  • Procedural asset generation from binary data keeps the PWA bundle size incredibly small.
  • Interactive map and logic tracking solve the game's notoriously obscure puzzle mechanics.
  • Full offline support makes it a perfect companion for handheld retro gaming sessions.
Weaknesses
  • Extremely niche audience limited to players of one specific 1987 NES title.
  • High maintenance burden if ROM extraction logic breaks on future browser updates.
Category
Target Audience

Retro gaming enthusiasts and ROM hackers

Post Description

I'll start by copying the comment I left on the Reddit post where I originally shared this project and then go into some more detail for this audience. (https://www.reddit.com/r/nes/comments/1umrnd5/i_made_an_inte...)

""" Castlevania II has always held a special place in my heart. I didn’t own it myself as a kid but I had a family member who did. This meant that I only got a few chances to actually play it, but that left a big impression on me anyway. I recently beat it for the first time and along the way I decided I wanted to build the most over-the-top guide you could imagine as an ode to the game. This is that guide. I hope you all enjoy.

Source code: https://github.com/baclap/the-ultimate-simons-quest-guide """

This is a Progressive Web App with full offline support. There are no static images or audio files used to create the guide. What it's actually doing is taking real binary data extracted from the ROM at build time, processing it at runtime in WebAssembly, and then rendering it using WebGL2. Similarly the game music is played from ROM-derived data through a Web Audio AudioWorklet that recreates the NES audio channels. There are additional curated JSON files that describe how all this data fits together on the map, the text from NPCs, the secret information, and so on.

This was really just a labor of love and something I'm proud to share. Looking forward to your feedback. Thanks for taking a look!

Similar Projects