Screenshots from the current build (v0.20.286), taken by the game itself. The boss fights are the ones filmed for the guides: one hero alone on Nightmare.
Boss fights
Scenery 3 · The hoar-mammoth · Lightbringer, NightmareScenery 5 · The fell-daeodon · Geomancer, NightmareScenery 7 · The hoar-bear · Alchemist, NightmareScenery 9 · The toll-master of the thyrn-mouth · Tempest, NightmareScenery 11 · The reading at brenvask · Sage, NightmareScenery 13 · The storm-prophet of halvnast · Occultist, NightmareScenery 15 · The answer at skeldnar · Pyromancer, NightmareScenery 17 · The seat's oathward · Druid, NightmareScenery 19 · The warping-master · Beastmaster, NightmareScenery 21 · The pit-keeper · Cryomancer, NightmareScenery 23 · The settling · Engineer, NightmareScenery 25 · The lantern-nester · Hunter, NightmareScenery 27 · The mound-head · Plaguebringer, NightmareScenery 29 · The slag-founder · Inquisitor, NightmareScenery 31 · The instrument · Arcanist, Nightmare
Menus
The main menuChoosing a heroThe four difficultiesThe first fight, in Vrethvath's yardThe results screen