Demanding >> the industry is fast and Riot is FASTER. Work life blend leans towards the work side but not as much as other reviews indicate. There's a lot that needs to get done but folks that that put in the extra effort are willing participants. Along with that note, I do find that Rioters are often terrible with time management. You will commonly see folks work 10+ hours a day, that's primarily due to their inability to utilize their time effectively.
Lack of standards >> Riot is almost adverse to standards at work. This creates a HUGE inconsistency from one team to another. Because of this, it is an unnecessary challenge for support organizations to keep up with the incessantly changing needs, tools, protocol, etc.
Squeaky wheel >> gets the grease. Riot's culture is more conducive to being overly vocal. The con here is the potential isolation of a personality type that can bring value.