Update 1 - full speed & better sound.
Update 2 - fix missing mouse cursor.
Update 3 - fix speed decrease in Pico8 0.2.0
Update 4 - support cartbios drag&drop and function keys.
What is this?
An emulator for the Fairchild Channel F, the first console to use programmable ROMs and a microprocessor.
The console was released in 1975, so don't expect much in the way of graphics, gameplay, or usability.
See Wikipedia for more info.
And what's that game running?
That's a homebrewed (i.e. - NOT original) game made by Blackbird and e5frog. You can find it here.
Any sound glitches are due to the emulator, not the game, by the way. (See below)
It pushes the capabilities of the console to its limits, so its quality is considerably higher than that of the other games for the console.
It's also anachronistic - the original Pac-Man wasn't released until 1980.
And how do I play other games?
In order to play other games, you first need the console's two BIOS files and the ROM for the other game you want to play. (Having these is up to you and they cannot be shared)
If you have those, simply drag & drop them one-by-one into pico-8. (E.g. drop each of the bios files, then drop the cart).
If you want to run the game included in the bios, drop only the 2 bios files, then press the reset button.
By the way, a BIOS is needed since the 'BIOS' included with the emulator is a homebrewed one which is only good enough for running a few games which don't use it much.
If you wish to copy the BIOS and ROM to the cart yourself - e.g. via cstore, they should be copied sequentially: BIOS SL31253 or SL90025 to location 0x0, BIOS SL31254 to location 0x400, and the cart to location 0x800. (Just like the Fairchild's own memory layout)
What are the controls?
In '1P' mode (default), the controls are:

arrow keys = move
Z = push
SF = rotate leftright
ED = pushpull
left shift = hold to control player