Content review for this game:
Pertaining to content listed in the upper left corner of this site.
"E" for everyone: As always, Bowser (the incorrigible bad guy) kidnaps Princess Peach, and it's Mario's job to save her. This game was made a little more recently than Super Mario Bros. 1 and 3 (1991), and graphics are more akin to a well made internet flash game than a 20 year old arcade title. But, like the previous in the series, the violence is extremely mild, and (as you may already know) mostly involves Mario jumping on the head of enemies, throwing turtle shells at their once owners, and having his horse-like dinosaur (Yoshi) swallow and then spit enemies across the screen. So, compared to today's games, this is as mild violence-wise as you can get.
Content-wise: Compared to the previous games in the Super Mario Series, this game got a pretty good boost in the graphics department, and the gameplay (including difficulty) became a little more main stream and accessible. Which means kids 6- could play around in many of the early levels--just don't expect them to get very far into the game.
Difficulty-wise: Like Super Mario Bros. 3, this game includes an overworld map, which acts as a gateway to the the side-scrolling platform levels that make up the majority of gameplay. Mario now has access to new power-ups like the cape ability (which makes him fly), which acts as a replacement to the raccoon ability in the previous game.
The biggest addition to this version is Yoshi, Mario's pet dinosaur. Throughout many of the levels, Yoshi is acquired by hitting certain blocks, and then hatches from an egg. You can then mount him and ride him like a horse throughout the level. He also has the ability to jump higher and longer than Mario, and swallow and spit out enemies with his long tongue. You can lose him by knocking into enemies, which will result in you falling off, and him dashing across the level. It is possible to get him back, but you have to catch him first.
The difficulty is far more balanced this time around, and because of this, I could see skilled 7+ year-olds completing a good chunk of this game. Also worth mentioning is, because of the button setup, you will probably want to buy the classic controller; if you use the Gamecube controller you'll have a hard time running and jumping at the same time.
Fun for: As I said, this game is far more balanced difficulty-wise, which makes it easier for younger audiences. But that doesn't mean the overall gameplay is more shallow for adults, it isn't in the least. There is plenty of hidden depth (some not so hidden), and though younger kids can have fun, adults will probably be the only ones to fully explore, uncover secrets, and finish the entire game.
Closing comment: This is probably the best Super Mario game in the entire 2D series, and has great graphics, unrivaled gameplay for its kind, and there's lots and lots to do. Content-wise, this is, of course, appropriate for all ages, and even some kids 6- could play parts of this game. However, kids 7+ and adults are going to get the most out of this game overall. So, I recommend this game for ages 7+.