Is saw 4 really THAT gory?

my friend said its not THAT bad...but hes the kinda guy that nothing scares him...i wanna see it cuz it looks like a puzzle movie..im 13 and me and my friend always watch scary/gory movies but my sister said "it shows everything" and she doesnt want me to watch it..is it really THAT bad? (like my bloody valentine iv seen that and i didnt think it was THAT bad)