Same Story as the Movie. Marty and Doc Brown are in the Year 1885 and try to get back to 1985.
According to the Manual this Game has 3 Levels. First is the Buckle-board Chase: You play Doc Brown riding a horse and you must reach Clara before she and her Buckboard make a dive down the Cliffs. As just riding would be to easy there are a lot of obstacles like Birds and Tomahawks Level 2 is the Pie throwing: Actually you throw not pies but the pie stalls. Throw them against Buford 'Mad Dog' Tannen to avoid him killing Doc Brown. The final Level plays on the Train, you play again Marty and must collect doc's special speed logs and you have to knock off the gang of Buford and the train engineers as they are not so happy that you stole their train. To make a long story short, this Game sucks and I'm glad this game has a Level select cheat so I actually didn't had to play longer than 5 Minutes to watch the levels.
The Graphic fits the game, it looks like from 1885. From the Characters to the Levels everything is absolutely bad, the lack of detail means you can't even identify who Doc Brown is and who Marty is.
Sound & Music
At least they have the Back to the Future Theme here. The other Music is boring and the Sound effects are bad, but still this is the best thing of this game.
The Controls fits the game, in terms of how bad they are. They react to slow, especially in the first Level.
One of the few games I will never play again - if somebody would give me 1 Million $ if I play this, I wouldn't.
This is one of the worst Games on the Master System, so avoid it like the plague.