You need a way to end the run early. If you max every upgrade you literally cannot die on higher corruption and I don't know of any other way to end the run. It took me 18 minutes to die on corruption 2 and I actively tried to lose. The healing in general is way too strong. You have 1 health on kill, which is insanely strong, health regeneration per second and the pickups which heal 20. And higher corruption gives you even more healing.
Also I would expect that with higher corruption the game would get harder, but it gets easier.