achievements might actually be cool, but should be done sparingly and in a very limited fashion; When you find crazy stuff in the game, for instance (small fire mario, minus worlds), or something rather impressive (beat the game in less than 18 minutes, beat the game without warping, etc), rather than "ACHIEVEMENT GET" the first time you get a mushroom.

Extending this to games like the Mega Man series (Beat Quick Man Stage first, kill Rock Monster boss without pressing start) or even Contra (Beat on three Lives) would be great. Just remember that less is more, and 3-5 achievements maximum is where you want to be.