The Sega Master System is unique in that it contains games that will run when no cartridge is installed. In the instruction manual there is a little note that tells you how to unlock a maze game in the hardware. Of course we all still have those manuals so I don't have to tell you how to do it right?
Well, just in case you have to press the main buttons and upwards on the D-pad (to be accurate, the manual says that this will allow you to "enjoy" the game, so if you play this another way you won't enjoy it). You then get 60 seconds to get this cute little guy to the end of the maze. The graphics are simple (blue maze, white walls, one sprite for the character) and the music is nice, but nothing to write home about.
There are two fundamental issues with this game. Firstly, there are dim lines that represent vertical walls, but sometimes there appear to be lines when there are none. I suspect that this is a glitch, but you can still get through the maze...until our second problem, the ending. The end is blocked on all sides. Try as you might you cannot get through. I know there are more levels because there is a level counter, but you can't get to them. Now, to be fair, the maze design is otherwise quite good (very ... mazelike ...) and this could only be in my version of the game (as firmware is upgraded the game could be as well).
Unfortunately, they still let an unbeatable game that EVERYONE who bought the system could play into the market, so I'm going to mark that, as opposed to whatever other versions may or may not exist.