-you need to warn people to use Bitcoin at the start page not somewhere else in details
-site almost gives the impression you can buy multiple tickets with one payment
-it doesn't really say HOW you are using random.org -Unless you provide details about how you are picking the winner you look like other lottery scam sites - as it is now, you could pick anyone to win, even yourself, and no one would know if you followed the rules or not
-using random.org is ok but unless others can get the same random data as you, it's not useful. You could just redo it until you get what works for you.
how to u randomize it? and you can buy multiple tickets at once