Evolva

Evolva is a third-person action game with a difference. After a bizarre biological menace falls on an alien world and sends out massive tendrils to infest the planet with its evil spore, four genetically mutable warriors called GenoHunters are sent in to destroy the infestation before it can spread to other worlds.

You can constantly develop the individual abilities of your four warriors by altering their DNA from the foes they have killed. e.g. kill a frog creature or a striding bird, and the GenoHunters can evolve the abilities of jumping higher and running faster.