I emulated the original not long ago and even though the graphics and animation hold up pretty decently, I think I should confirm this game's replayability factor. It's nice while it lasts but that isn't saying much, especially if you are not a fan of The Simpsons (I am not... I like this game, though)
As for Final Fight: Double Impact , I think it did pretty well (at least, I liked it a lot). If Capcom were smart, they would consider a port of Cadillacs and Dinosaurs , or better, Alien vs. Predator (I know, I know, it ain't gonna happen)... T^T