The world of Amarna was a prime location for the goa'uld Osiris, and site of one of his most productive naquadah mines.
Osiris kept the location of this world, and its import, secret from all other System Lords, so at the time of his banishment, it remained unknown. It was used to fuel the bulk of Osiris's military ventures, and was thought to be one of the richest veins of easily accessible naquadah in the galaxy at that time. A secret well worth keeping.
The temple that Osiris had constructed to house his stargate on Amarna was part of the disguise. It actually housed many secret passages and sealed doorways, making entrance and exit difficult, and masked the purpose of the world, so that any discoverer would believe it to be merely a temple site to his ego, and not the massive mining operation it actually was.
When Osiris was banished, thousands of years ago, the slaves on Amarna escaped through the stargate to other worlds, leaving behind the mine, and the worlds true purpose. Though not entirely a desert, the region that the mine is located is very inhospitable, and the mine was reliant on constant supply from space to keep operating.
The SGC has rediscovered this world during a routine investigation of gate addresses, and upon a closer inspection, discovered the mine. A military survey team has been dispatched to investigate the mine, and report back home.
System Lord spies have detected the communications about this world, and managed to uncover their own information about the existence of the mine, and its rich supply of the mineral. Legends of Osiris's never ending supply of naquadah have long been told among the goa'uld, and their location has remained a mystery until now. A force is dispatched to slaughter the Tau'ri currently present on the planet, and seize control of the mine for the System Lords.
Surprised at the gate, the SGC guards left to watch over their exit are dispatched by Ashrak, and a trap is set for the returning survey team.
The SGC's mission to survey the mine has become a mission of simple survival. They must fight their way through the temple, eliminating all of the System Lords, so that they may safely get control of the gate, dial home, and escape. The System Lords are intent that no human survive, and will ruthlessly defend the temple and the gate, killing all who cross their path.
The key to this world is survival. Watch your corners. Scientists will be aggressive with poison, and there are infinite nooks to hide those dangerous turrets in. Commandos have several excellent vantage points in the central open gallery, and even the ledges are accessible, and in shadow.
Keep moving. Keep firing. Watch for traps, and know that ashrak love this temple. Ambush is key, here. If you're a soldier, fire into any open area, and around all corners. Watch your back, and look for a good vantage to get the drop on groups of System Lords.
Scientists have several excellent locations to set up a strong base, with healing turrets, defended by their .50 cal. These strongholds will allow your commandos and soldiers to venture out, find a victim, and return to heal up and do it again.
If pinned in your spawn, remember there are multiple doors to get out. Run clear, take the first corner, and regroup to return and retake the area outside your spawn. Don't ever fight on the enemy's terms.