This is a sample / prototype copy of Mazu: Guardian of the Tides for the Famicom. This cartridge was used to test the game when we were developing it.

Another test to try to figure out what was going on between the consoles versus the emulator.  There is no mirror mode, once again the player only has 3 hits instead of 4, etc.  

There might be other differences in the games too.  I know one of the versions you can only access the later stages via passwords. There are some stages with enemy placement diferences, etc.