Aww! Super C! I remember the fun i had with this game right here! Not as hard as Contra thats for sure, but still a quite badass retro experience! Its a must play for any retro gamer out there! And just leaving this out there, is you get the last boss of the game with the L weapon you can find a blind spot crouching infront of the boss and just shooting in diagonal, you can beat the last boss in around 15 seconds like that! But you didnt heard it from me! ;D
I am currently playing the gbc version of this game, it's a pretty nice port and helps you keep track of all the levels you've completed. The first mario game is a classic and a must have. Every gamer in the world should give it a go at least once, it's weird it hasn't gotten a remake yet, being one of the most important Nintendo titles.