I made this using UE4 and Maya 2016, following the excellent Shooter Tutorial series by Andrzej Koloska: shootertutorial.com/
Here's a vid showing some of the AI types that were made in the tutorial series, using Blueprints. There are the flying drones, a wall-climbing spider, as well as a couple of soldiers. There's also a giant robot that eventually beats me senseless. The tutorial series used pre-packaged assets, but I made and animated all these guys from scratch using Maya just to see what I could do. I also made the tunnel in Maya and imported each section and prop piece by piece into UE4. I did NOT make the sounds, muzzle flashes, fire, or the blood 'i'm taking damage' texture overlay.