Dude, Where's My Sequel?
Some games are great in concept and sometimes in their execution. Unfortunately, poor sales or just lack of interest means these great ideas don't often the proper praise they deserve. Sometimes it's probably best to leave them as they are lest some big company buys out the licence and produces a game that's no where near the original, other times a small indie developer takes it upon themselves to create a game heavily inspired by the games they've played (with often varied results.)
In any case, these games were either good or bad but they all still had heart to them and hopefully they'll get the a second wind of popularity one day.