Why GrogVM

AI has the whole industry in a frenzy, and everyone's dying of FOMO to build something with it.

I'm guilty too. I've got at least three AI-built side projects sitting at 80%, left to rot because they were solutions looking for a problem: not useful, not educational, not fun. And honestly, after the last 15 years I'm too scarred to seriously consider building another business. It turned out I just had to look back at what I loved as a kid and jump into the deepest rabbit hole I could find. For fun.

Enter GrogVM.

The Secret of Monkey Island is one of the first things I remember about PC gaming, the first graphic adventure I ever played. I have an extremely vivid memory of being at a friend's place in the mid-90s, watching him play as this weird pirate sprinting across Mêlée Island with a mug of grog, the stuff so corrosive it eats straight through the metal, pouring it from mug to mug all the way to the prison before the grog eats through and there's nothing left to melt Otis' cell lock. I was in shock, mind totally blown.

So, when looking for a fun way to spend some time, shouldn't I just have replayed it, like countless times before? This time it didn't feel "enough", so I decided I'd try rebuilding the engine that ran it all, to see how the magic actually worked. And I chose to do it on the platform I love and have spent my whole career on, the browser. This is my love letter to Monkey Island, LucasArts, and Ron Gilbert.

Even though I'm privileged to have plenty of time available to spend on side projects, I'd never have embarked on something like this if it weren't for AI. Regardless of how fun something may be, it's extremely unlikely anyone would dedicate months (years?) of their own life to it, especially a monumental one that's already been done, works perfectly, and is openly accessible to anyone (looking at you, ScummVM).

I've been working in tech for more than 20 years, but I have no experience in the gaming industry, so my role here is to use what I've learned over the years to steer the work in a direction I believe in, while AI (Claude Opus 4.7, 4.8, and then Fable 5) handles the bit-flipping.

So this is just for fun?

When I started this a few weeks ago (on May 25th, 2026), I thought this was an opportunity to have fun while learning how to build a non-trivial project with AI. That FOMO I mentioned above contributed to it, but the first and foremost goal was to have fun. Within a few days I realized there was another opportunity, to contribute at least a bit to the preservation of the absolutely outstanding work done by the LucasArts team first, and the ScummVM volunteers later. None of this exists in a vacuum: ScummVM and the people who documented SCUMM over the last two decades made this kind of project possible. GrogVM is a separate engine, not derived from ScummVM source, but it absolutely stands on that preservation work.

Everyone working in the industry knows that documentation is a double-edged sword. When well written it's very useful, but it takes a lot of effort, and the more you write the more likely it's going to get stale over time. I realized that, while there are resources available on the web about SCUMM (Script Creation Utility for Maniac Mansion), they are scattered across websites and forums, hard to consume, sometimes conflicting with each other, or even only available through the Wayback Machine. That's why this project ships with extensive documentation, not only about the engine itself, but also about every SCUMM detail we could reconstruct from the reverse engineering process. And because this documentation doubles as the AI's durable memory, it's treated as a first-class citizen; not an afterthought, or something a developer was forced to write.

In addition to this, GrogVM comes with an extensive set of inspection / educational tools. A full-fledged disassembler (disgrogate), a headless harness driving the virtual machine to probe real game files and build integration tests including an e2e game walkthrough, a screenshot tool (mugshot), a real-time VM inspector, and a resource explorer that allows you to deep dive into game files and their content.

Project status

As of June 16, 2026, GrogVM is capable of playing the CD VGA version of The Secret of Monkey Island end to end in a Chromium-based desktop browser, both the English and Italian variants. Visual polish and a few AdLib-only effects are still in progress. Any other format or variant has never been tested and may be broken. No other game is supported at the moment, but Monkey Island 2: LeChuck's Revenge is the next (and likely last) target.

Install a copy you are allowed to use in the Library and check it out, or read how it was actually built: the struggles, the dead ends, and the parts still unsolved.