I just bought the N64 version of the Gameshark and am somewhat satisfied with the results. I own No Mercy, which is plagued by glitches. Gameshark allowed me to gain all that I had lost in the game by unlocking all the secrets. A great peripheral for those who are stuck in a game. Unfortunately there are some glitches. Apparantly some games won't work with it, as my Resident Evil 2 kept locking up when I tried it with Gameshark. Also there are reports of it breaking after a few months of use. All in all a good tool, but buyer beware.