"1 is standard with stack sizes. "

I thought hero's play in hand 1 was standard, too, but this comment provoked an important concept that I admit I still don't completely understand. Namely, how does stack size influence the play in hand 1? What if villain had a substantially bigger or smaller stack? Or is this comment directed at hero's stack size? If so, again, what would differ if hero's stack was much bigger or smaller...

Sorry for the newb question, but I am trying to get better...