The Evolution of Video Game Monsters

Okay, so this was something my friends and I were kicking around one day, after playing Metroid Prime 3: Corruption, and I hope it sparks a lot of discussion: What evolutionary event causes monsters in video games to turn out that way. The Metroid Prime series is a "prime" example of this(pun very much intended).

In the series, you travel to several different planets, each with their own unique ecosystems, each with their own unique life forms, but all having similar life forms.

I'll start with(and mostly focus on) Corruption, because this is the one that's still fresh in my mind.

Planet Bryyo has 3 creatures I'd like to focus on: The Reptilicus, The Reptilicus Hunter, and the Warp Hound.

The Reptilicus and R.Hunter are both from the same evolutionary starting point, but they differ in a key way: The regular Reptilicus can teleport, and the hunter can turn invisible. The Warp Hound does exactly what it sounds like, it can teleport.

Now, what makes this interesting is that the Warp Hound and the Reptilicus teleport in two unique ways. The Warp Hound blink out, then port back with an animation. The Reptilicus ports out with an animation, and ports back in with an animation. Two different methods of teleportation, for two different creatures. The Hunter is different. He render himself visible only to thermal imaging. Now, what could have possibly influenced this evolutionary change in these creatures?

Now, not to spark a religious debate, but Darwinism states that changes occur over time, and very minutely, with occasional mutations. What minute changes could work slowly enough to allow for teleportation? Specifically, two DIFFERENT kinds of teleportation, that clearly work in two different ways. Or, what random mutations would cause teleportation. I am of the thinking that the most likely form of teleportation is that of shunting to a smaller, parallel dimension, traveling a relatively short distance, and then shunting back, traveling a proportionally longer distance.

What possible event(s) trigger teleportation as a viable method of defense and evasion. While awesome, it doesn't seem, how shall we say, natural.

Alright, I'm done. At the very least, I hope this sparks some ideas. Sorry about the lack of pics, but I have terrible photoshop skills and all I could really would do would be something about the FSM probably.