I feel like Walchice is both overwhelming and underwhelming at the same time. First and foremost I'd never figure out this mission if not for the video by "Spoons & Ducks" which taught me that terraforming exists. There is just no army that can keep those tanks and Dante away, not with the economy you get. But more importantly, the turrets, stardust and stinger, are more or less useless during this mission, because you never get the time and economy to build enough of them to make a difference. As "Spoons & Ducks" suggests, your only option, even on normal, is to quickly destroy the three factories using glaives and your commander and then just wall yourself off as soon as possible. Once inside the walls, maybe you'll actually be able to build a few stingers, if you still have any economy left by that time, but it's not likely they'll do much at that point.
This mission could be more tower defensish, in my opinion. But most importantly, this mission is impossible to complete with just the tools you get when you approach it. You must go around to other planets to unlock terraforming and maybe some other useful things to be able to complete it.
P.S. Oh and yes, you need your commander to be at least 4th level so you can output enough damage while being sturdy enough to survive.
