* Let's start with the SceneryPorn: ''[[http://www.youtube.com/watch?v=Kc_dGJxQC60&fmt=18 NyLeve's Falls]]''.
* The first appearance of the Skaarj. In the first part of the Rrajigar mines, steel bars lock you in a narrow corridor, then one by one [[DarknessEqualsDeath all the lights go out]]. You hear a menacing growl, and then alarms blare and the action music starts as a Skaarj scout leaps from a hidden alcove to attack. However, there's a way to escape from that area. [[spoiler:Charge the Dispersion Pistol and do a [[RocketJump Dispersion Jump]].]] You'll miss the great moment, however.
* ''[[http://www.youtube.com/watch?v=Sw7s0NR4Vlk&fmt=18 Bluff Eversmoking]]'', a large, fully explorable location with a lot of attention to detail. It also has some of the best subplots.
* Multiplayer-wise, ''[[http://www.youtube.com/watch?v=G2HH16uEKI0&fmt=18 DMDeck16]]'', by far the most awesome deathmatch level ever created in the series.
** Also ''[=DMMorbias=]'', a.k.a. the Colisseum of Destruction. Even with just one weapon, it's mayhem at the maximum level. And a helluvafun.