I'm kind of bummed out that you didn't use the ravens more (aside from the very last room, where they're ultimately pointless). Is there anywhere else you could fit them in? Perhaps in the room with the wooden castle tileset in lieu of the ball'n'chains?
That aside, this is a pretty good level. Quite difficult, but I guess that is to be expected for 5-8. Here are some issues worth noting:
A lot of this first room really bothers me. It's very, very easy to get hit by flying yellow cacti, and since you've loaded the room up with them, it's borderline unfair at times. Perhaps this
would be an excellent point to incorporate ravens (e.g. have the mini ones circle stone blocks that are in the way of the pinwheel, have the bigger ones circle moons that are also in the way of the pinwheel, etc). Really, one or two of these Piranhas is fine, but when you oversaturate them like you've done, it makes the area more annoying than fun.
Two things here: the flower ground cuts off below Yoshi (right wall), and that star cloud is in a really inconvenient location.
You can ride the arrow lift to the left and up on to the roof. There's nothing up here besides thorns though, so...
Might be worth shifting the Piranha down one tile so that his first two yellow shots act as threats while you're both on the yellow platform and on the ground. Right now, they hit the wall and pop.
Minor cutoff here, and it seems odd to use the boss door when you're using it again in the sublevel directly after this. Also, consider putting a second middle ring either here or in the next room.
I missed a red coin too .. not sure where. I'll see if I can get it on your next version of the level.