I don't know if it's been mentioned before, but for me the difficulty scales up until it's practically impossible to beat a wave with current enemies and income, but then it drops back down a lot once I reload the time.
I'm a bit curious as to why the cheaper investments (not counting Lemon Stands) become so ridiculously more expensive than the, well, expensive ones in the late game. When at 400, a Newspaper Delivery costs 114.1 sept., while an Oil Company at 500 costs 12.7 sept.
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