The objective of Hyperrogue is reach a highscore by collecting treasures. Each treasure is native to a different land, and are collected in different ways. Common treasures are spawned on the ground frequently, and are typically found in early lands, though a few extremely dangerous later lands like Cocytus have common treasure. Rare treasures are also spawned on the ground, but only in special locations which tend to be remote and are sometimes heavily guarded. Dropped treasures appear when boss monsters are defeated. Enclosed treasures appear when certain blocks are destroyed. Power treasures have an effect when their tile is stepped on. Compound treasures require some process to be obtained other than simply picking them up, but multiple tend to acquired at once. Many lands contain treasures which can be acquired in multiple different ways.
Treasure does not only determine a player's score, it will also (along with Kills) unlock new Realms and increase monster spawn rate. Each realm provides a treasure which can only found there, like Gold or Silver.
Treasure is usually abundant, in that there are more than 10 per realm, but actually collecting that many might be a challenge.