This is the correct answer. OP, you really shouldn't feel bad about not responding to people emailing you about a free-to-play game. Besides, most of them are

This is the correct answer. OP, you really shouldn't feel bad about not responding to people emailing you about a free-to-play game. Besides, most of them are probably just writing to tell you how much they like it, or wanting you to partner with them. You don't have to answer any of them. Just put up an autoresponder explaining that this is a free game and you're a university student and can't respond to email. I mean, this is what Google does and many/most people love Google products.