Those player sprites look REALLY great!! In all honesty I haven't previously come across such high-quality player sprites, with some rare exceptions such as DD's creations. Admittedly, cat-Rin looks a little bit strange, almost as if she's...wearing a fur suit, as opposed to being a real cat. Unfortunately I cannot provide any suggestions on how to improve that particular sprite. All of the other player sprites, as well as the Earth Spirit look very nice. As for the enemy shot graphics, I believe both, the knife shots below the arrows, and the straight lasers at the very top would do well with more white to them, and thinner colored borders. It would make them easier to see against colored backgrounds in-game.
It's a bit of a bummer that you're currently not open for requests or commissions, though certainly understandable. If, one day, you do open commissions, I'd be more than happy to borrow your services if you allow me to! I've been pondering the idea of creating a fully-fledged Touhou fangame as of lately, and a sprite artist of your capability is someone I'm desperately looking for. No rush though, these are just thoughts for now. I'd be honored if you would consider me as a possible business partner. :)
