PICO-8 is a "fantasy console" - an 8-bit gaming system realized entirely in software, and designed to resemble something from The 8 Bit Era Of Console Video Games, with similar limitations on its graphical and sound capabilities. The PICO-8 FAQ describes it as "similar to a retro game emulator, but for a machine that never existed."
The console is aimed at game programmers, and thus includes everything needed for game programming right out of the box, including editors for code, graphics, and sound. The machine specifications are intentionally limited, both as a way to reproduce the 8-bit feel and also as a way to encourage expression and ingenuity: it has only a 128x128 pixel, 16-color display, a sound chip with only a basic set of oscillators, and 32KB of data per cartridge.
One clever feature of the PICO-8 is that because its data carts are so small, the data can be steganographically encoded into the cart's image file - that is to say, the picture of the cart actually is the cart itself.
A 16-Bit successor
, Picotron, is currently in it's Alpha state, and only has seven titles released on it as of the time this i last edited (4/27/24), which all of them came from the Picotron Game Jam.
Its website can be found here.
