I have an account on my kids Ipad that doesnt get much play time.I am still in 2ER level there, and it is brutally boring!
My other accounts I got going right away at the start of the season. Most everyone else was at roughly the same level, so figuring out the optimal strategies for turret placement, pathing the heavies to the ER was important and interesting.
Now, it seems most of the players that are still at 2ER have maxed out all their turrets, which makes it impossible to get any ERs. And they have maxed out barrage, which means they can take out both ERs in a couple seconds.