artifact

The main goal is to build a city with all the facilities (farms, lumber mills, quarries, foundries, barrack, etc.) and to survive. If you can do that, the next goal is to find the Artifacts. There are eight Artifacts scattered on the map and you (or your clan/alliance) have to hold them for a certain time (it always change, usually for 8 hours). Each Artifact has a name (Air, Crystal, Earth, Fire, Water, Wood, Spirit and Bone) and special features (more defense, faster growth, etc.).

The game in itself is free, but you get only 3 hours a day of play and a limited number of games at the same time. Then you can upgrade your player level by paying a one-time fee and get more hours/games. I've been playing this wonderful game for two years without paying, it's not a problem.
If you pay $35 (and then reach the Citizen level), you can join or create a clan. Clans are a big part of Artifact and a lot or games are clans-only.

Currently, it's Artifact 2. The main differences with the first version are the nice graphics. You can also chat with other player, leave messages on built-in message boards and, most of all, earn rewards. The reward system is deeply complex. You get various medals for various actions.
Here is the complete list of rewards you can get:

Awards based on Total Score
Winner - Has won a game.
Ace - Has won 10 games.
Ace of Aces - Has won 100 games.
Solo Winner - Won a non-beginner game without being on an alliance at any time during the course of the game. Also known as the "lone wolf" award.
Pillager - Has killed 1M population.
Marauder - Has killed 10M population.
Conqueror - Has killed 100M population.
Treasure Hunter - Has found 10 Artifacts
Explorer - Has found 50 Artifacts
Master Explorer - Has found 200 Artifacts

Awards based on Blitz Games
Blitz Winner - Has won a Blitz Game.
Blitz Ace - Has won 10 Blitz Games.
Blitz Ace of Aces - Has won 100 Blitz Games
Blitz Solo Winner - Has won a Blitz Game without being on an alliance at any time during the game.

Awards based on "Best Games" Played
Silver Population - Has built a city with 500,000 population.
Gold Population - Has built a city with 1,000,000 population.
Ruby Population - Has built a city with 5,000,000 population.
Emerald Population - Has built a city with 10,000,000 population.
Sargent - >100,000 troop kills (not counting militia or settlers)
Lieutenant - >500,000 troops killed with a 1.5:1 kill-to-loss ratio or better (not counting militia or settlers)
Captain - >1,000,000 troops killed with a 2:1 kill-to-loss ratio or better (not counting militia or settlers)
General - >2,000,000 troops killed with a 5:1 kill-to-loss ratio or better (not counting militia or settlers)

Download Artifact at:
http://www.samugames.com/artifact/

An artifact is something that is made by humans -- not simply in the anthropological sense, but generally, in all contexts.

Lossage in image compression is an artifact resulting from the application of a human-made algorithm; the true image* is distorted indirectly by the programmer.

In scientific experiments, artifacts can be from several sources, usually related to the observation of the primary data (mis-calibrated equipment, etc.) but can also be due to environmental factors (EM radiation from overhead fluorescent lights, heavy metal ions in laboratory water, etc.). In short, anything which obscures the observation of the true phenomenon of study is an artifact.*

Of course, anthropologically, anything that humans make and leave behind is an artifact. In this sense, bones and skeletal leavings, ancient as they may be, are not truly artifacts: they are remains.

Ar"ti*fact (?), n. [L. ars, artis, art + facere, factum, to make.]

1.

A product of human workmanship; -- applied esp. to the simpler products of aboriginal art as distinguished from natural objects.

2.

A structure or appearance in protoplasm due to death or the use of reagents and not present during life.

© Webster 1913.