Eternal Trials, then True Endless

The community wiki describes each stage as a pick of one map, one weapon, and a growing perk set. Stage 1 offers two perks. Stage 2 offers four. The count rises by two. Losing wipes the chain. The score formula printed there is the number of stages you have won, squared, times 10,000. From stage 5 the gold floor is at least 11. Seven achievements hang off the mode.

True Endless sits on Totend and is called out as its own mini-mode in the 2.11 notes, alongside twelve other mini-modes. A force-quit in the middle of a trial is a common question. The publisher has not written what that does to the score, so I am not filling it in.