Sorry about the vines! If I had had more time, I would have figured out a way to make them more fair, but I was really crunched at the end.
For the diamonds, in levels 2 and 3 there are these animated tufts of grass, and if you plant a seed on them an item will pop out. This is never explicitly required, and left to the player to discover. I think these would be the ones you're missing.
For level 1, I'm not sure which one you're missing. There's one in a flower bulb right at the start that's easy to miss on the first pass, since you have to backtrack after getting the shears, and if you prune too much at one point then you can't jump the wall to get back. It's just a guess, though.
Anyway, thanks for playing!