Silencer
 

I remember there being a free MMORPG, based on Mars, I think it was hosted by GameSpy. It was more of a take off on capture the flag. You had to go to the other side's base and steal components from them and take them back to your base. The game was based on a dystopic Mars, and it was a 2d platform game.

Was it Soldat?

I had the same idea, take a look at Abandonia Reloaded.
Soldat

Not Soldat, it's older, darker, and the sprites were larger.

Found it:
http://en.wikipedia.org/wiki/Silencer_(game)

Silencer by Mind control Software

Here you can find other info about it:
http://www.mind-control.com/gameDetail.php?gameID=02

It says "This game is out-of-print"...
Edit: seems an open source project, check this link.

i checked that wiki link. doesn't seem like freeware to me. it's clearly abandonware. project that unlocked the client was opensource, however technically that was illegal. Only the company that created the game didnt' mind much or complained - ergo abandonware.

Technically you're right but they want to release it freeware soon.
We have to wait.
http://community.arsia-mons.com/index.php?showtopic=141

http://i.gjcdn.net/imgserver/game-he...50/11802_2.jpg

CYPHER
The Official Free Online Multiplayer Hacking Platform Shooter
http://www.CypherGame.net
Trailer: http://youtu.be/VjxKty_zl28

Strategy, tactics, and fast decision making are all needed in this incredibly intense game. CYPHER was constructed in a way that allows for enormous amounts of skill. This gives users a rich experience, but does require learning the fundamentals. A ‘Capture the Flag’ dynamic is applied to this interesting, complex and dangerous environment. Cypher is unique as it was built from the ground up to support cooperation as well as competition with others in real-time. A free chat and game network with dedicated servers provide for solid gaming. It is still in development, but it is online and playable. Cypher features an automatic updating system that distributes the very latest version to all the players seamlessly as the game is developed. This project has been almost five years in the making, with the map editor starting a year before that.

Features
• Free online lobby network that provides for chat and game matchmaking.
• Increase your hacking skills and strength as you level your Agent with completed online missions.
• Leaderboards display the top players across the globe.
• Automatic updating system so players always have the latest version.
• Jetpacks, Lasers, Blasters, Plasma’s, Detonators, and heath packs are just a few of the many tools your Agent can utilize.
• Entirely open environment with endless possibilities for strategy, teamwork, and sabotage.
• Controls are highly intuitive and precise, giving players the opportunity to employ skill on a massive scale.
• 10 unique maps that can support up to 8 players in any arrangement of teams or FFA.
• Integrated exception reporting system to give developers bug reports on the fly.

Background
The plot of CYPHER is the overthrow of the tyrannical Martian government. In the not-too-distant future, colonization of Mars has been completed and the new government is being influenced by evil corporations. These organizations are rife with corruption and greed. The populace seems to not notice or care, lulled into a false sense of complacency by the media as their freedoms are stripped from them. From the darkness, a collection of underground computer hackers emerges to find valuable secret information which can lead to the downfall of the destructive forces that have taken over the planet. YOU are one such hacker, bent on revenge and justice, trying to bring about that change.

Throughout the civilian world are public-access terminals. Using a special device, you are able to hack into secured networks and steal secrets from the government. They will try to stop you at every turn, killing anyone they track down carrying their secrets with their murderous orbital satellites. Competing agents, out to make a name for themselves or representing different agencies, will also attempt to kill you to slow you down or profit off your hard work. Working alone, or in covert teams, with a host of technology on your side, you are able to overcome these challenges, collecting data you will be able to one day use and open the eyes of all civilians and expose the lies of those in power.

Download CYPHER (XP, V, 7, 8 )

http://forum.CypherGame.net
https://twitter.com/CypherGame
https://facebook.com/CypherGame
https://youtube.com/user/CypherGame
https://google.com/+CypherGameNet