I've run across two bugs. I don't know if they've been reported before. One may be CHIP specific, the other is most likely general.

1) Focus issue with controllers. With a CHIP starting with a controller plugged in, the controller is not immediately recognized.

Start Pico-8; try the controller, nothing happens; open the log file - a controller is shown as plugged in; go back to Pico-8; the controller now works. So you have to start Pico-8, shift focus away from it, go back to Pico-8, controller is now recognized.

This has been mentioned in the CHIP forum, but I don't know if it has been reported here.

2) Pico-8 does not work with a simple game pad.

I tried Pico-8 with Next Thing's (CHIP) supplied controller, and a Logitech Precision gamepad. Neither worked. Both recognized the start and fire buttons, but not the D-pad. I then tried a Logitech F-310 (controller with analog sticks). Pico-8 recognized this. Pico-8 is looking for an analog stick for direction control if you use a controller, not a D-pad.

There is no setting exposed to the user to change this behavior. As Pico-8 uses just 6 buttons for its control, it would seem that support for simple D-pad game pads would be appropriate.

"2) Pico-8 does not work with a simple game pad."

I don't know about with CHIP or the desktop version, but I will be starting work soon on web-based gamepad support for my P8 site. I noticed zep added mobile controls with the new site update, which I will be integrating into my site, and I assume those same exact hooks (detecting input with JS and sending the signal to the web player) can be used for gamepads.

Like I said though, that unfortunately doesn't help at all with CHIP or the desktop app though.