The progress in my achievement counter shows 69/69 but the achievement hasn't unlocked yet. I've unlocked all the others. Anyone get this to unlock?

Why does this game take so much of my computer resources? I mean, it's just a puzzle. But it loads my computer like "The Witcher 3: Wild Hunt"..

Is there any opportunity to play May and June monthly challenges? I bought this game only yesterday, and I like that hard mode

How can I set the hard mode?

How do you get the petal to spawn? I completed the game in all 3 difficulties, did the monthly challenge and even let it idle on the same pic shown in the trailer for a few hours, but I never saw the petal appear. Any tips?