Console Observatory 0.3.0: open any Game Boy ROM, with cartridge banks made visible

Superseded by 0.4.0, which adds DMA-aware sprite writers and explanatory tooltips. Download the latest release unless you need this one.

Console Observatory is a native desktop Game Boy teaching lab. Run a game, pause it at any moment, and follow what happens in the CPU, memory, and graphics hardware.

What's new

• Open any Game Boy ROM up to 8 MiB (File › Open, Ctrl+O, or drop a file on the window), with every cartridge controller SameBoy emulates (MBC1, MBC2, MBC3 with clock, MBC5, MBC7, MMM01, HuC1, HuC3, camera, TPP1). The 32 KiB limit of earlier versions is gone.
• Cartridge · banks panel: the CPU's three cartridge windows linked to every ROM and RAM bank, lines showing what is mapped right now, banks shaded by how much code ran from them, a plain explanation that adapts to the cartridge, and every bank switch with its effect ($2000 ← $02 · ROM bank 1 → 2). Run until the bank changes stops right after the next switch.
• Bank-switching demo (File › Bundled examples) with a short lesson that presses A and stops at the real switch.
• Battery saves: a .sav file next to the ROM, loaded on open and saved automatically.
• The built-in startup program now leaves the machine in the state real games expect.

Download

Platform	File	How to run
Windows 10/11 (64-bit)	console-observatory-0.3.0-windows-x64.zip	Unzip and run console-observatory.exe. Not code-signed: SmartScreen may ask, choose More info → Run anyway.
Ubuntu 24.04 (x86-64)	console-observatory_0.3.0_amd64.deb	sudo apt install ./console-observatory_0.3.0_amd64.deb

SHA256SUMS.txt lists each file's checksum. No commercial game is included.

Good to know

• Original monochrome Game Boy only; no sound output.
• In this version, sprite bytes written by DMA (most commercial games) show no writer; 0.4.0 adds that.

Built and verified by the Release workflow from this release's commit (same checks as CI). Details: docs/VERIFICATION.md.