Oh wow, this has a lot of wonderful stuff going on it it. Keep up the great work.
ohhhh do you play as a little ninja dude? Hahaha this whole time I thought you were playing as a bird with ninja stars! Not saying anything bad about the art, I think it's beautiful, I just could have sworn it was a parrot or something (I thought the eye in the shadow part of the character was the beak) and you have a feather item so I just assumed. Cool game though! Excited to play it
The star stays where you left it -- unless it was stuck in the ceiling, in which case it may be below where you left it. When you die and respawn at a savepoint the strays are removed from the world and returned to you.
Some care has to be taken when throwing them to assure you'll be able to get them back without having to die first. They act predictably when they bounce off something, so you should always have a good idea of where they will end up.