I've been thinking of other wrinkles to put on the scenarios for AMF. I suppose a lot of us grew up seeing on TV, in books and in our plastic toys the old T. Rex vs. Stegosaurus battle. So maybe that could form the basis of a 2-player variant scenario? I tried it, starting rm with the AAS Carnosaur genotype and rrrr with the Ba Stegosaur genotype (not completely historical I know) and it made a fairly challenging scenario.
Another interesting one I tried is Carnosaur v. Triceratops (Ceratopian ABGa). Interesting result: rm won! He decided to go Marine and it really worked out well.
More interesting was the next one, Tyrannosaurs (Carnosaurs rm) vs. Brontosaurs (Brachiosaurs rrrr) which was won by the former.
Another one I tried is Primates PP (mmm) vs. Velociraptors (Deinonychosaurs APSS rrrr). The reptiles won on a nearly frozen world without predators.
I tried the Canoids (mmrrr) v. the Feloids (mmm), which the former won. This wasn't quite as interesting as some of the other matchups, probably because the two creatures are too similar.
In a 2/3 frozen world, GODZILLA (rm Carnosaurs AAS 1-5) were twice struck with Pandemic during the Cenozoic and then bambi (mmm Pecoran Ruminants BGS 1-3) acquired SS and roadrunnered him right out of existence. By the end, the score was 17 (herbivores) to nil.