This game is quite a classic game, and here is how I review it:

Difficulty: 8/10
The difficulty can be both pretty easy to pretty hard, the difficulty changes to easy to hard as you progress through the game, so it isnt random difficulty.

Depth: 8/10
The length of the game is alright, 8 worlds with 4 levels each, which makes 32 levels in the entire game, which is pretty good for an NES game, not too long, not too short.

Story: 7/10
The story is pretty basic, and just like any of the Mario games, Princess Toadstool (Peach) is kidnapped by King Koopa (Bowser) and Mario must fight through the Koopa Troop to get her back.

Assictiveness: 10/10
I always loved playing this, and I can keep playing this for hours over and over, it does not get old.

Sound: 8/10
The sound effects and music is pretty good and that is why it is pretty famous, it is catchy and it can get stuck in your head, it is pretty addicting humming the tunes.

Graphics: 7/10
The graphics are kinda basic, I seen better graphics on the game, the Japanese version of Super Mario Bros was really great, it looked like a Mario game, the US version isnt bad, but it could have done better.

Overall Game rating: 9.2/10
If you didn't play this game yet, you should go play it, so I reccomend this game. Go play it.