I PLAYED ET when I was younger (and didn't know better). There is a REASON why they buried those carts.
American Gladiators for SNES! Loved the show, HATED THE GAME!! Pressing A button until your arm falls off just to have your ASS handed to you is NOT fun, believe me.
Back To The Future for NES! My fucking GOD, was that a BITCH to get through, and get this, the ending SUCKED ASS! You played and played and broke your controller to see a black screen with THREE WHOLE LINES OF TEXT as your ending. My GOD, why did I BUY that? Maybe because my stepbro wanted to see if anyone could BEAT it. I did, and FUCK!
Oh, and while I didn't play it, according to the Angry Video Game Nerd, Dr. Jeckel And Mr. Hyde for NES is one of the WORST:
http://www.youtube.com/watch?v=6M_4Yqk65f8 (he disabled the embedding of the video for some weird reason).