I have to say that was a pretty great video, and that you are a lot better than I am at the game - I'll have to make a custom map for you to play
I'll be playing a custom map for my channel next, let me know if you make something awesome :)
Nice video! I have found a weird trick (dont know if it works in the newest updates) here is the image. Painted in MS paint so its horrible.
Do the enemies on the left just walk around to the right? Definitely something I'd have to test, sounds awesome though.
If enemys are already on the left, they usually keep attacking the wall and do not walk around to the right. (from personal experience at least)
No for me it's the opposite the enemies just walk to the right no matter what. The walls on the left just have to be really wide.
(again only from personal experience)
This is because the enemy AI is really simple and trys to find the path of least resistance. I usually have a really powerful turret setup with holes on either side, and put walls on any other openings. the enemys assume they can walk through the holes on either side, but get obliterated by the turrets.