For 13: From left to right, top to bottom, click the left button if the heart is facing up, right if it's facing down. You have to interpret when the hearts overlap.
Suggestion: Show more decimal points on the stats page. I like seeing increasing numbers for things like bounces, gives me a sense of progress, and I don't get that with "1.24M".
The only thing I'd like different so far is I'd like the checkmark at the end of the level to not obscure the board. I like the emotional satisfaction of seeing a completed board.
Yes, they come from the game engine, which is the same.