1st one looks like a classic normal game due to the crit built the player went for. On top of that the Gnar didn't even try to kite.
2nd one was a well timed Q and a stupid missplay of Lee
Don't take my critique too harsh, I just used to play League a lot in the past 8 years - if that's an excuse
Actually, the Crit build is ranked and that's how I build Sion lately, feels easier to carry with crit rather with tank