FreeIntv is a libretro core Intellivision Emulator, intended for use with RetroPie on a Raspberry Pi 3. The primary goal was to allow my wife to play Astrosmash without needing to use a keyboard.
A few unique features allow easy play on a typical SNES or PlayStation style joypad.
The first is the "mini keypad" that allows you to view and press keys on a small keypad that appears in the lower-corner of the display while L or R is being held.
The "X" button is also mapped to the last selected keypad button, giving quick access. In Astrosmash, for example, you can leave "3" selected to enable instant access to hyperspace.
Finally, the select button lets you switch the left and right controllers. Some games expect the left controller to be player one, others expect the right controller. This isn't a problem if you have two controllers (and don't mind juggling them) but users with only one controller or using a portable setup would be effectively locked out of some games. Pressing select from either controller with swap the left controller for the right and vice-versa.
I'll post more about it sometime in the future. For now, you can download it here:Link 1: SourceForge Link 2 (old): Amazon S3 Update: It's on GitHub now: https://github.com/libretro/FreeIntv The libretro ‘buildbot’ should soon start producing pre-compiled binaries for other platforms.