The Pit Of The Artificer is a repeatable dungeon located in Cerrigar, Scosglen. Just northwest of the Cerrigar Waypoint you’ll find the Artificer’s Obelisk (Portal Activator). This is where you’ll gain access to the dungeon, so remember it well.
As for the dungeons themselves, they are timed but they don’t merely have a numerical timer like The Kurast Undercity does. Instead, a gauge will appear on the right side of the screen, with an hourglass marker slowly progressing from left to right.
A separate, white triangle marker on the gauge represents your progress. For each enemy you kill, the gauge will fill slightly, moving the white triangle closer to the end.
You’ll need to defeat a large number of enemies to fill the gauge completely, which causes the portal to the final boss to appear. You’ll need to completely fill the gauge and kill the boss before the hourglass reaches the end to win, and the faster you do it, the better your rewards will be.
Each time you complete a run with time to spare, you’ll unlock higher difficulties of The Pit Of The Artificer, which represent difficulties up to (and surpassing) Torment 1 to 4.
If you die in The Pit Of The Artificer, you’ll incur a time penalty, which starts as a slap on the wrist, but the time penalty will increase the more you die. Ideally, you’ll want to run difficulties where you can get through quickly, without dying.