When the “Resident Evil 2” film came out, there was a flash game on the official movie website that let you combine DNA from various animals in order to engineer the ultimate monstrosity.
It wasn’t an action game, it was a lab simulation. The recipe you decided on either resulted in a living organism, or a waste of chemicals. That was the whole game in a nutshell.
Once you managed to produce a Frankenstein’s Monster, you could further evolve it by adding more and more DNA.
“Yes! My Lobster-Camel hybrid has grown stronger with an infusion of Rattlesnake blood. I’ll add Penguin bone marrow next! Nyuk nyuk nyuk nyuk.”
I’m exaggerating a bit, but you get the point. It was lots of fun for a flash game.