itch.io

That's the release times for different sponsor levels. You'll notice different dates next to each one. They get access to it earlier than people that are just hanging around waiting for it for free.

Generally speaking each person publishing their games sets up their own rules for their works, so you should either look around their page for some info on how they handle things or question them if they don't seem to have anything posted.

Only to a certain extent. If you paid money for the game, that just means you supported Hexatail. You're not getting a different version. If you are a patreon then you get early access to the game, but it is still the same one that is eventually getting released publicly.

It's always on your side when your antivirus program blocks it. It doesn't mean anything is wrong with it. Every program has the potential to alter your computer in a negative way. A virus is just a normal program that's been made to do harmful things to your computer. Antivirus software doesn't like programs from unknown publishers. You just have to add it to your trusted list.

He is completely wrong about alright. It is and has been a proper word in English for well over 100 years. There are a few ignorant people that insist that it isn't correct, but it has long been recognized as acceptable even in academic settings. He is technically correct about "got," but he's also wrong. If you were writing a paper for a school or professional organization you wouldn't want to use "got" the way you are, but people have long used it incorrectly in informal speech. It is  acceptable to as a sort of slang. People in native English speaking  countries use it the way you used it quite often.