Here is the price evolution of the upgrades:
Speed: +1 every 5 points
Life & Sight: +1 every 10 points
Land: +1 every 3 points.
If you're really far in the game (like me), the only upgrade you have to spend your points on is Land, because with a lot of people and a extremely fast building speed, buying Land upgrade is like directly paying more Population limit. But if you don't upgrade Sight, don't forget to not make your people appear only at one point of your land.
Man. I got approximatively 500 land tiles. I have so much people that my PC lags.
My population limit is 1660. I've got every achievment except Idle game.
I started playing this game today. Omfg.
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