Blu3Flame

As has been mentioned you can change how this is handled in the settings. Either finish early (the default), finish the exercise, or only finish the exercise if it's one that switches sides. I switched it to finish every exercise and found it makes a big difference.

Raspberry Pi foundation commited to producing them until at least 2022. There was a production shortage recently due to a component pipeline delay.

Go to the Retropie Setup and there's a menu in there someone that lets you pick additional themes to install.

All the themes that come with Retropie can be previewed here: https://github.com/retropie/retropie-setup/wiki/themes Maybe there's something there that will be suitable to use or edit.

You can switch it into NES or Famicom mode via the config files in the theme folder.

Missing the bios file?

The SNES/NES mini themes are easily the best. Highly customisable, support the resolution of the Picade, and have support for the new Retropie features such as favourites.

Might simply be that you have to force the Pi to output HDMI via the config file.

Bluetooth, yes. Wired, kinda, but you'd have to play with the back off so you can plug it in.

I've never figured out multi disc. I just have them as split entries.

Been using my Picade most days and it turns out it's pretty great for some DS games. Space Invaders Extreme 1 and 2 are essential and are perfectly suited to the control setup.

Use this theme.

Are you sure the ribbon is in as far as it can go? What power supply are you using? Is the HAT properly pushed onto the pins?

The screen is fantastic, really vibrant.

If anyone gets stuck building and setting theirs up I'll help where I can.