The Simba are a species in Serious Sam 2.
The Simbas are a species that lives on the planet M'Digbo. They are short blue people that usually wear stereotypical “African” garb, such as loincloths. Based on their appearance in the game, the Simbas can live in either in small villages or huge cities.
As of Serious Sam 2, it seems that they are under siege by Mental's forces, as one of his bases have been spotted on their home planet. This is most likely because they're an intelligent species, which means that they quality to be exterminated by Mental.
Despite looking primitive, the Simbas have some surprisingly advanced technology. They have created the Clawdovic, which is basically a homing bomb. They have also mastered flight, as they have a device, the Simba Bomber, which can fly. Finally, they have equipment such as rocket launchers and Zap Guns, which suggests they have connections to more advanced technology via an unknown source.
They also have remarkable architectural skills, as they were able to build a large city, Ursul, which seems to have many, many tall buildings in it. Dialogue in Kronor also suggests that the Simbas can fly spaceships, as some of the pilot prisoners on that planet are Simbas. In short, the Simbas are much more advanced than they look at first glance.