Hey Death,
you are right, the late game is not properly balanced. The whole perk system was drastically changed just a few weeks before launch so we couldnt really balance-test it thoroughly against our high end enemies. As we are a very small team we always have to spend most of our time developing and sometimes the testing comes too short.
At the moment my impression is that if you manage to get by without ever really losing a battle, the Bros outscale our enemy progression slowly but surely over the course of a playthrough.
Rest assured were keeping an eye on this issue and wont hesitate to take measures once we feel we have enough feedback.
Cheers!
PS I wouldnt go so far to say “no challenge” by the way, as most people tend to complain the game is too difficult :)
