There's a new Atari 2600 demo out
It comes with executables for emulators and real h/w, and both are PAL. The "real h/w" one hangs after one of the scenes in the MESS a2600p driver. The "emulator" one runs all the way through but the rotating 3d cube (yes, really) is very glitchy. (I haven't seen a video from real h/w to verify everything yet, but supposedly the latest Stella runs it correctly).
It's worth watching even for non-MESS-testing purposes incidentally, there are definitely some "how the heck did they do that on that hardware?!" moments