Gauntlet: Slayer Edition

Have the Orcs and Grunts masteries to at least silver to make this easier. Start with the Siren's Lute relic to make yourself briefly ignored in order to get past certain parts that may be difficult, as when multiple spawners appear.

At the start of world 3, level 2 are two demon spawn sites that are separated with a set of doors. Collect the key from the pedestal and unlock those doors. Remain at those two spawn sites and kill as many demons as possible. You can also destroy those two spawn sites and continue by lowering the bridge to find another set of two spawn sites. Remain on the bridge and kill the demons.

Reach the last area of World 1 level 1 when four shrines spawn. Do this under the Insane difficulty setting to increase the spawn rate. This is also made easier with a assistance of a friend playing the Valkyrie. Go with your friend into a corner have have them block enemies while you kill them.

Go to a level that features a lich. Get to low health and stand in front of its attack.

Play "Tombs III" and progress to the last stage, where the short arena fight ends with two liches. Kill them, then remain on the spike trap until you run out of lives. Select "Retry" to resume at the beginning of the arena fight. Repeat the process as many times as desired. You can also destroy the food in this room to progress towards the "Eating off the Floor - Gold" achievement.