There is a NON-STEAM game I play sometimes which have the best days behind .
Developers left it, but it's still very playable. Unfortunately community is very small these days. Even in rush hours there is still max only one full server. Most of the day servers are empty, but in afternoons and evenings (European Time) there is almost always someone to play. The game is called Babo Violent 2. Give it a try!

http://www.baboviolent.net/

All three game clients are compatible. If you want to see some gameplay first or anything there are links at the bottom of the http://www.baboviolent.net/ web page.

Once you play a Babo, you will never leave! :)