I thought about making a backup but the update actually reset all the curve of progression, also it implement achievements, so it has no sens to keep the past save :)
A little bug I found, all upgrade except for spawnrate have a max cap and can't be click after it say max but spawnrate can be go beyond and it stop spawning anything. It's like the upgrade got more stage upward but it's obscured. It take my money when I click on and it flash red same as when I doesn't have enough money to buy an upgrade.