20 years ago, I coded a demo for the gameboy with graphics done by a gizmo. Back then, I was only really able to test my code on a single emulator, not on the real hardware. Turns out, that emulator got its hblank interupts slightly wrong and was off by one scanline, which garbled the first screen which was supposed to be a spinning 'icebird' text.
Now, after 20 years, there is a patched version of this demo that fixes this first screen.
Dawn.gb is the original rom, Dawn_fixed.gb (unsuprisingly) the fixed version.