I've played the German version of the game a while ago and I must say that it's one of the best MMM Episodes. It has some good puzzles and is very funny. It's also a very long on for a MMM Episode, it's not a short length game.
I think one doesn't have to have played all previous MMM episodes. There are some references to old games, especially to Episode 8 (,which, luckily, has an english translation: http://www.maniac-mansion-mania.com/index.php?option=com_contentask=view&id=26&Itemid=37), but the game isn't unplayable without a vast Maniac Mansion knowledge, there are only a few jokes which one might not understand completely.
I think one doesn't have to have played all previous MMM episodes. There are some references to old games, especially to Episode 8 (,which, luckily, has an english translation: http://www.maniac-mansion-mania.com/index.php?option=com_contentask=view&id=26&Itemid=37), but the game isn't unplayable without a vast Maniac Mansion knowledge, there are only a few jokes which one might not understand completely.