It plays them with a Honeybee converter.
As I stated in my review and showed in the video, the multicart I have gave me a bit of trouble on the menu screen (it looked like it was displaying in PAL on an NTSC set) but once I got to the actual ROMS it was fine.
I also tested Famicom copies (all HK pirates I think) of single game carts - F1 Race, Super Baby (?), and Super Mario 2 JAP with the adapter and they worked fine.