But the game plays a little bit different from the arcade. For starters you seem to begin the game with ability to fire vertically. There's 5 empty power slots so presumably the Sun power gives you the arch shot instead (I haven't check all the powers out yet - they seem to take ages to appear). There's no lava pits in this version. Instead that part of the level is a sort of cavern. In some places you have to go underground to get past trick parts. The game manages to keep all of the monsters, backdrops and even the fireball pits, but they don't appear in the original order - again not really a problem though. There's no stones in the game - instead there's sort of flying wings objects that appear from the ground. You can shoot at these and they turn into objects. The levels themselves are also different. Instead of entering the temple you go directly onto the next round without stopping. At the end of about six levels you are faced with the Large Blue Demon. If you kill him you are then awarded a repulse and time bonus.

All in all not a bad effort considering it's the Master System. It's not arcade perfect as you might imagine but if you're a fan of Rygar it's well worth finding for a game or two.

Some more info from Brendan Duffry: Reasons for this game not working on a US system:

1.  The Japanese Mark III / Master System had a 44 pin cartridge connector, and the US / Europe / Australia systems had 50 pin cartridge connectors.

2.  The BIOS of the non-Asia SMS systems check for a header in the game ROM, which Asian games do not have.  The Mark III did not have a bios and the Japanese SMS had its own type of BIOS. So here are the scans.  The label art seems more interesting to me than the other versions.