For anyone confused, press space to start.

Also, I don't know why, but it doesn't react to the trackpad, and instead only reacts when I use the touch screen. No idea if it's just a side effect of not having a mouse, having a touch screen, or something in the programming.
Aside from that, these types of puzzles are great, and I really enjoy this game

the game doesn't start.

good game but needs elements to keep you playing

I can't even get past the starting screen, what are the controls?

It feels like sudoku!