Nicely done. Playing through it a second time I felt much more confident in what I needed to do to orient the book correctly to safely move flowers.
I found a small bug: if I push a flower vertically with the open book, but the flower is against the edge of the level with nothing else on the other side of it, the book breaks apart vertically. I noticed this in the penultimate level, and it's easier to test in the final level. The same thing doesn't happen if I try to push a flower against a wall block with the open book, so it seems to hinge on a subtle distictinction between "flower can't move because it's against a block" vs "flower can't move because it's against the edge of the level". I don't think this behavior can be used to cheat the penultimate level, but I haven't investigated much.