i bought this game a while ago but i uninstalled it do i need to buy it again?
No, you don't all you need to do is find the email from itch.io saying when you purchased buckshot roulette and click the link in it to bring up the latest files for the game. (It's explained further here when you try to buy the game and click "I already paid for this...": https://itch.io/docs/buying/already-bought)