Here's one we missed you might like. Species: ALRE is an evolution simulation game which puts you in control of life itself. It entered Early Access on Steam back in September, with a Linux version arriving last month.

Species: Artificial Life Real Evolution is an evolution simulator that allows you to create, destroy, observe and tinker with life on it's never ending, harsh march of refinement!

The developer claims the simulation going on is "Simulated from the very first principles of evolutionary science" which includes each creature being uniquely defined by genes, with children being a slightly random version of their parent(s) and the environment also plays a factor in this.

Not much of a looker for sure, however it seems it may very well be the type of game where the style to it doesn't matter a great deal. Considering everything you seem to be able to do, exploring the environment and tinkering with life itself does sound quite appealing.

The price is planned to increase when it leaves Early Access, they're not currently giving out an estimate of when that will happen.

Find out more about it on Steam.