Bloodborne.
I don't know how much it really "changed"-- I mean. I guess if I didn't adore the game I wouldn't have a hunter's mark tattoo on my wrist... The main reason I say bloodborne changed my life, however, is because it was my outlet-- my happy place during some pretty mentally bad years of my life. Instead of pouring my energy into self destruction, I poured it into getting half decent at this game. Mind you, I don't really play games. At most I can say before BB I was playing like... pokemon and fire emblem. The PS4 I got on was referred to as "The bloodborne machine" since that's the only game I had and would play for a long time.
I was god awful, and even now I can't say I'm great (though I can't say that to friends because they always say "You did a blood level 4 run, ofc that means you're GOOD" but like... I struggle too much to be good, and it's definitely not 1000+ hrs into this game kinda good. I should be better.)
It kicked off my interest into the old classic gothic literature, which inspired my writing style. It helped me with my awful moments so much I got the hunter's mark tattooed over some old SH scars. And it has brought many fun moments and times with friends after I started playing for fun instead of an escape.