Missile Command 4-4-83

This is the only PAL 5200 Missile Command prototype known to exist.  The code is different than the NTSC version, but there are only a handful of noticeable changes.  The first change is that in the code there is a variable set to successfully pass an NTSC/PAL cartridge check which was to be introduced with PAL 5200s in an attempt to block NTSC games from running on PAL systems.  This check (introduced with the 2 port BIOS) would only be triggered on a PAL 5200 which was never released and can only be seen if running in an emulator.

Next, the splash screen has copyright of 1981 instead of 1982 for some inexplicable reason even though the 5200 wasn't released until 1982 and the PAL version was to be released in 1983!  It's not even the arcade game's copyright date as that would be 1980.  I have no explanation as to why this was changed other than by error.

There also appears to be an error in the screen height when played on an actual PAL 5200 (these don't exist so you need to use an emulator).  Normally the regular NTSC version of the game sets the screen size a little larger to compensate for PAL displays, this prototype doesn't do that so it looks squashed if played on a PAL 5200.  Once again, this can only be seen on a PAL 5200 (which doesn't exist) or an emulator.

Finally there's the speed.  Since the prototype is tied to the refresh rate of the screen the whole game runs slower.  Oddly the retail NTSC version runs at a normal speed on a PAL 5200.  It seems that this prototype was a first attempt at trying to get the timings down for PAL systems.