I was recently listening to an episode of Vicious Circle which reminded me of old video games I used to play back in the day. They were discussing battle toads and I suddenly flashed back to the Game Boy version of that game. Holy shit, what a fucking exercise in cruelty. You'd survive (Note I don't say PROGRESS) a few levels before being mercilessly smacked the fuck down. Good times.
Mario Land was another game boy game I played the everloving shit out of. The graphics weren't anything to write home about, but the gameplay was mostly classic mario (with a few fucked up spots, like shitty "landing" detection.. you'd jump on a block but fall through the edge of it,)
Mario Land 2 and Wario land fixed these problems.
There were also several entries from the Final Fantasy universe for the Game Boy. I played (and enjoyed) them all, but they did seem to get much easier as the numbers progressed. The last one (IIRC) was Final Fantasy Adventure, which while much like Zelda and awesome, wasn't all that challenging.
I look at many of the games out today and while the graphics and sound are awesome, something seems to be lacking in the game play department. It may be that I'm over 30 and turning into an old curmudgeonly motherfucker, though.