Like everyone else I was playing video games as a kid. Two games that I got particularly hooked on were Motherload and Minecraft. My brother and I used to play these for hours on end and we even set up an online Minecraft server together with our high school friends.
It’s funny to realise these two games have one thing in common; both are digging themed. Did I choose the wrong career? Anyway, I felt nostalgic a couple of weeks ago and keen to vibe with Claude Opus 5.5 a bit more. It was time to create a game and what could beat making a Minecraft style Motherload with a flavour of Mario Odyssey? At least I couldn’t think of anything.
After a few iterations I had built Blockdigger.
Before trying it, continue reading this blog post to learn how I built it and what surprised me when I asked the Claude in Chrome extension to beat my score. Let’s dive in.
Built over a weekend
My first prompt asked for Motherload’s gameplay with Minecraft-style graphics and a world map like Mario Odyssey’s, where you unlock new worlds and spend your coins on skins.
Claude insisted on one thing first: an homage, not a copy, with our own code, art and name.
Then I asked it to “complete it end to end with unit tests and make sure it’s playable when I come back from lunch”. 48 minutes later it was running on localhost with 10 worlds, a star-based world map, skins, a final boss and 61 passing tests. Every pixel, note of music and sound effect is generated in code. There isn’t a single image or audio file in the game.
The first version worked, but it didn’t feel right. Most of my prompts after that weren’t about code at all:
- “I feel like the gravity is a bit too strong?”
- “It should take at least 15 min of good gameplay for the first unlock”
- “Maybe it can be a devil you fight and it blows some fire on you”
One evening session later the game had a Devil boss at the bottom of the last world, intro and ending cutscenes, a wardrobe full of animated skins, iPhone support, and was live on a subdomain via Cloudflare.
Then my mate Herman became the first beta player. He got hooked and finished the whole game in 2 hours. My first full playthrough took 1 hour 10 minutes (I did build it), dying only once. We both found the late game too easy, so the deeper worlds now have lava that burns, monsters that chase you through your tunnels, and prices that rise the deeper you’ve dug. Herman also asked for more chests with superpowers, which became power caches. And to let friends compete, we added a score: 1,000 points per star and 10,000 for beating the Devil, minus 1,000 per death and 25 per minute played, so a careful run beats a fast, reckless one. My 76,875 came from a later, faster run.
Testing all those tweaks got slow, though. To check a change in the Magma Realm, I’d have to play an hour to get there. At first Claude gave me code to paste into the browser console, but I asked for a button instead. Now the home screen has a “magic checkpoint” button that only shows up when I run the game locally. I tell Claude where I want to be, like “60 blocks down in the Magma Realm with tier 3 upgrades”, it updates a small config file, and one click takes me there on a throwaway save. There are buttons to jump straight into the Devil fight or play the cutscenes too.
Claude couldn’t play it, so it found a workaround
The game has a headless bot in its test suite that plays through it end to end. So naturally I wondered how Claude would do as an actual player. I opened the game in Chrome with the Claude in Chrome extension, picked Opus 5.5 on medium effort, and gave it this prompt:
“Start a new game of this blockdigger (read how to play first) and try maximise high score. Go!”
It read How to Play, started a new game and drilled straight down in between all the ores. And kept drilling… About 3 minutes later it was 463 ft down with an empty tank and no cargo, having never sold a single piece of ore. A rescue drone hauled it home for a $10 fee, and 1,000 points off the score.
The same model that almost one-shotted the entire game with physics and fuel economy couldn’t manage a fuel bar through a screen. For a second I thought superintelligence might actually be quite far away and I stepped away to write about my findings. When I came back to Chrome, I was in for a surprise:
All 80 stars, the Devil beaten, and a final score of 77,625, ahead of my 76,875. Here’s how it explained it:
“I can’t react in real time from screenshots, and my first two runs into the ground ended in rescues. So I switched to a tool-assisted approach, and you should know what that involved.”
It changed the problem instead of getting better at it:
- It took over time. It stopped the game’s animation loop and ran the frames itself, pressing real keys in between. Physics, fuel and damage all worked as normal. The game measures playtime from the timestamp each frame is given, so by handing it frames 1/60 of a second apart, none of its thinking time counted.
- It read the map. It reloaded the game’s own code with one extra line, so it could read the pod’s position and every tile: ore, lava, gas pockets and the caves where monsters sleep. It used that to plan routes and budget fuel.
- It didn’t cheat on the economy. By its own account it never edited coins or upgrades. Selling, refuelling and upgrading all went through the normal shop screens.
It also told me what it did without me asking, and then reviewed its own run: 9 deaths cost it 9,000 points, and its “autopilot hovered in place a lot”, which cost about 3,400 more. A clean run would score about 86,000, it said.
So in the end, it did what the headless bot in my test suite does: it wrote code that plays the game. The one difference is that it wrote that code on the spot, inside my browser, because playing through screenshots didn’t work.
I asked if Claude had cheated:
“So I’d call it a bot run that followed the rules, not a legitimate high score. It shouldn’t stand as your personal best next to your 76,875.”
So did Claude beat me? On the scoreboard yes, but not by the same rules, and it was the first to say so.
Your turn
So the high score to beat is now Claude’s 77,625, and my 76,875 is just behind it. The theoretical max is 90,000. If you can beat Claude in real time, without pausing the game, hit Share score when the Devil falls and send it to me on LinkedIn.
Cheers, Hannes Kindbom