I played Super Mario Bros. 2 last night with my Game Genie. It kept freezing at level 4. So I took it out and blew on the contacts, and then I played it until the very end. Originally I was not going to use any warps. When it froze the second time, I warped to world 4. And then to world 6. I misremembered it warping to world 7. I should go back and replay it just to experience level 5.
The Game Genie is a great device. Its only drawback is that you can only enter 3 codes. I used infinite lives, infinite health, and Princess's moon jump, which basically lets her float in the air forever. It comes in very handy. i don't think I could beat the game without the Game Genie, though. It's really really really hard.
I got a coin in level 7-2 just for giggles because I knew I wouldn't be able to get a chance at the slot machine (7-2 is the last level.) And then, when the cast scrolls by, they misspelled Clawgrip as "Clawglip." And Ostro is the real name of the end level boss, not Birdo. So Nintendo themselves have been getting Birdo's name wrong ever since.