Sludge isn't that satisfying to remove, I think because of how difficult it is, kinda like how Powerwashing simulator starts extremely satisfying and by the end it kinda feels like a chore because everything is so innefective and you're on the same spot for a long time. I just went back to level one to make money. At some point I could print 500 bucks every 7 seconds, compared to >2min at later levels for what, 2k? Both of these made me feel bad as the game progressed, instead of excited. With every step it was double the effort for barely 50% more rewards, when most incrementals give you 200% for 50% more effort...