* AnticlimaxBoss: [[spoiler: Babbit. As you have Ada at this point, you can use her headshot skill to rip off a giant chunk of his HP, making the final boss fight ridiculously easy. The Scorpion is a lesser example, given that you don't fight it directly.]]
* DemonicSpiders: The SEAS robots, in particular the executioner due to its damage bonus against every unit type.
* EnsembleDarkhorse: the Spinosaurus. Appearing in exactly two missions of the original campaign, it is nearly ubiquitous in user created maps.
* ThatOneLevel: The prison break mission.
** And the last level.