My earlier post about Seventh Cross Evolution reminded me about how much I like E.V.O.: The Search for Eden on the SNES. The game has a whole lot of grinding in it, and the game maybe is a bit rough around the edges, but creating the ultimate monster is great fun and something to be treasured. There's a lot of ways to play through the game, and later eras can see anything from dinosaurs, carnivorous mammals, birds, humans, or mermaids all battling the final monstrosity that claims to be a "Caveman".
You can check out my E.V.O. Let's Play on YouTube with this handy playlist link.