Well today I want to introduce you all to a game called Cortex Command. Despite the fact it’s not even nearly complete you can download some good community made mods that make up for the lack of ‘official’ content. Also you can make your own - or simply tamper with pre-existing units.
You can download a trial version for free which you can use to try it out and you can then buy it (and all future updates) for a pretty decent price.
Cortex Command is set a few hundred years into the future, where the now cybernetic human race is able to travel between stars and has already met several alien civilisations.
Interstellar trade and prosperity reigns, but there is always an ever-expanding frontier to explore and exploit for precious resources. In this gold rush of galactic proportions, fantastic adventure and brutal competition awaits.
An extract of the story from the games website.
Anyhow - I suggest you have a look.