btw this is the youtube video that inspired me to make this thread and buy a book.
I wonder which Greg Egan book I'll read next.
edt: I mostly love hard sci fi just because it tends to make something more original and engaging. Having more equations or being harder to follow doesn't make it harder sci fi imo.
Instead it's hard sci fi when the book deals with the consequences and restrictions of real life. I wouldn't say the Martian is less hard sci fi just since it deals with a smaller story or spends less time convincing the reader that things really work this way.