I finished the EE for Alpha Omega. It's a really fun map, and I love the art direction for it. Rushmore's dialogue throughout the whole main quest is hilariously campy nationalism, with him punctuating just about every one of his lines with propagandized rhetoric, like shouting "MANIFEST DESTINY!" after talking about retrieving a particular item that has been stolen by an intruder on the base.
He's basically the CoD Zombies equivalent of Liberty Prime, satirizing American nationalism and imperialism with incredibly amusing quips.
Bonus points for him going into a brief tract about your next objective involving collecting a bunch of random objects, including George Washington's dentures, before experiencing a power surge and having the objective immediately change to the much simpler "please replace my batteries". He's easily my favorite part of the map, and the fact that he communicates your objectives clearly and concisely (without the next steps being extremely obvious) makes it all the sweeter.
If it weren't for Rushmore, the sheer fanservice of having Ultimis and Primis interact would definitely make up for it. Play this map with subtitles on, so you don't miss all their back-and-forth exchanges.