Its a fun little idle game, but I do'nt like how the tasks are done. The best way to play is to check task -> Buy correct upgrade once -> Check tasks again -> By upgrade. Which is completely against how you're meant to play an idle game. The 'optimal' play style is fighting the intended play style.
I'd prefer the usual 'reach level 10 in x', that's tracked retroactively, so you can just go and claim them all at once after a load of upgrades instead of having to swap back and forth between the two.