It doesn't look pretty, but it sure is fun!
Other than that, it's very similar to Super Mario Bros. for the NES, however there are some differences. Koopas now explode ( this explosion can kill you) and the majority of baddies are new. Don't worry, you can still stomp Goombas! Fireballs are no longer here, but bouncy balls are used in place and now can collect coins and bounce all over the screen to attack enemies.
For the Mario platformer fan, it's a no brainer. Essential playing.