Hello and thank you for your comment!
I've changed the way "clicks" work, to be inline with the game's lore: click, hold and drag the mouse around, as if you were petting the cat.
And you can filter the upgrades in the shop by cat and category (power and speed), so you can get what you want easier!
If you have any more questions, I'll be happy to answer!
As always, have fun and stay healthy!