Thanks for playing! The rocket dudes were actually set up to seek high ground and spam you from there. I never got around to finishing squad behaviour, but they were supposed to eventually contest after all melee enemies were down. There are also actually 3 upgrade shops - The one on the high ground left of the enemy spawn may have been a bit hidden haha. They stack, it's just not super extreme. The damage upgrade is also a bit of an invest - it does end up one-shotting melee enemies with all 3 acquired. The balance is def a bit (very) wonky though.
Again, thanks for playing and commenting!