Developer BadComputer has released his new homebrew game Astro Climber—a vertically-scrolling arcade action platformer for the Sega Master System / Mark III—with full public download access.
The game, launched on 20 October 2025, was created to mark the 40th anniversary of the Mark III’s original launch in Japan. It features 32 stages, a grapple-hook mechanic, and an oxygen-refill system, all developed within the limits of the classic hardware.
The ROM is offered for free on itch.io, meaning you can download and play it right now, either through emulation or on original hardware using a flash cart.
We’ll be publishing a full review of Astro Climber on Metal Game Solid very soon.
Download the game here.
This a cool little game! Played it on my Pocket and it’s quite enjoyable.