Hello! First of all, you did a great job, and I really liked how everything works. It's a wonderful! Regarding your question, no, I don't accept payments via bitcoin because of the contentious legality of such payments in my country.
I'll do. I am currently working on a large set of items for a role-playing game in a fantasy / medieval setting (currently contains more than 320 items). Perhaps, after finishing that, I'll make another tileset for a platformer game.