Deuteros

The sequel to Millenium 2.2 alas never got a PC port but this excellent rts game is definitely worth a play.
The setting:
Taking place after the events of Millenium 2.2 you start with control of a ravaged earth and a quest to retake the stars and discover the origin of a mysterious alien signal. Unfortunately those mutinous methanoids are still around to cause you problems.
The graphics:
Although very basic by today’s standards the 2D graphics and artwork are atmospheric and absorbing and somehow really make you feel part of the Deutreros universe.

The gameplay:
The game uses a mouse type point and click interface to control all elements of the game such as research, construction, ship control and combat etc. and is actually very intuitive to use. Where this game really beats its predecessor is that as the game develops monotonous routine tasks such as resource balancing become automated which allows you to focus on the developing war between you and the methanoids. Combat is rather simplistic the winner largely being determined by who has the most combat drones in any engagement but it is still somehow fun to watch your bunch of little green dots engage with the computers bunch or red dots.
Where this game falls down a little is after conquering the first two or three solar systems things become a little repetitive with an endless repetition of the standard pattern of attack, take over, clear out the methanoids from the system, find the piece of the alien device and move on to the next.
The story:
The game play is similar to millenium 2.2. You begin by training your people into groups in three disciplines research, construction and piloting. Don't bother training lots of researchers though as you only need one group for your earth base, similarly only two or three groups of construction engineers will be needed as you will soon be able to research an automated substitute.
Once that's done you can begin researching basic tech such as shuttles, orbital factories and other ships such as asteroid miners and transports. Once that's done begin launching a factory into orbit and start your expansion across the solar system.
You will rapidly colonise the Moon and begin mining the asteroids for rare minerals and then you will have your first contact with the methanoids when you find one of their stations orbiting the more distant planets or their moons. You can trade with them initially but beware expand to far and it's war, if you trade you will get an advance warning when a defector gives you plans for your first weapons. After that you will need to start fighting back, unfortunately the first methanoid station you conquer will self destruct after you board it but once you research the self destruct tech you can deactivate it and take over the station saving you from having to build a replacement.
Fortunately capturing a methanoid station will lead on to the discovery that they have teleportation technology to shift their resources between stations just as managing your ships transporting minerals between your bases starts to become a pain. After that it's a simple progression to taking out all the methanoid bases in the system. Eventually this will result in your reception of an alien transmission and discovery of part of an alien device in orbit somewhere in the system, then you can research the necessary tech to travel to other star systems and repeat the process gathering another piece of the device in each system until you can finally construct the completed device and complete the game.